Remove quickstart docs.
Remove quickstart docs.

It is now obsolete by skia.org. All the relevant doc is hosted there
now.

BUG=None
R=mtklein@google.com

Review URL: https://codereview.chromium.org/1138833005

VRToxin-AOSP/android_external_skia,nfxosp/platform_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,TeamTwisted/external_skia,PAC-ROM/android_external_skia,shahrzadmn/skia,ominux/skia,HalCanary/skia-hc,shahrzadmn/skia,pcwalton/skia,PAC-ROM/android_external_skia,PAC-ROM/android_external_skia,MinimalOS-AOSP/platform_external_skia,google/skia,YUPlayGodDev/platform_external_skia,qrealka/skia-hc,MonkeyZZZZ/platform_external_skia,todotodoo/skia,HalCanary/skia-hc,timduru/platform-external-skia,nvoron23/skia,pcwalton/skia,OneRom/external_skia,UBERMALLOW/external_skia,aosp-mirror/platform_external_skia,ominux/skia,todotodoo/skia,MarshedOut/android_external_skia,PAC-ROM/android_external_skia,MonkeyZZZZ/platform_external_skia,geekboxzone/mmallow_external_skia,VRToxin-AOSP/android_external_skia,boulzordev/android_external_skia,timduru/platform-external-skia,Infinitive-OS/platform_external_skia,boulzordev/android_external_skia,invisiblek/android_external_skia,qrealka/skia-hc,tmpvar/skia.cc,OneRom/external_skia,boulzordev/android_external_skia,w3nd1go/android_external_skia,w3nd1go/android_external_skia,todotodoo/skia,PAC-ROM/android_external_skia,YUPlayGodDev/platform_external_skia,spezi77/android_external_skia,timduru/platform-external-skia,TeamExodus/external_skia,todotodoo/skia,BrokenROM/external_skia,nvoron23/skia,AOSP-YU/platform_external_skia,HalCanary/skia-hc,BrokenROM/external_skia,BrokenROM/external_skia,AOSP-YU/platform_external_skia,nvoron23/skia,qrealka/skia-hc,MinimalOS-AOSP/platform_external_skia,VRToxin-AOSP/android_external_skia,vanish87/skia,noselhq/skia,pcwalton/skia,spezi77/android_external_skia,PAC-ROM/android_external_skia,OneRom/external_skia,aosp-mirror/platform_external_skia,geekboxzone/mmallow_external_skia,MarshedOut/android_external_skia,spezi77/android_external_skia,boulzordev/android_external_skia,UBERMALLOW/external_skia,ominux/skia,ominux/skia,pcwalton/skia,HalCanary/skia-hc,MarshedOut/android_external_skia,Infinitive-OS/platform_external_skia,Jichao/skia,geekboxzone/mmallow_external_skia,TeamTwisted/external_skia,nfxosp/platform_external_skia,pcwalton/skia,MonkeyZZZZ/platform_external_skia,nfxosp/platform_external_skia,BrokenROM/external_skia,TeamTwisted/external_skia,UBERMALLOW/external_skia,AOSP-YU/platform_external_skia,Hikari-no-Tenshi/android_external_skia,OneRom/external_skia,timduru/platform-external-skia,Jichao/skia,TeamExodus/external_skia,aosp-mirror/platform_external_skia,geekboxzone/mmallow_external_skia,TeamTwisted/external_skia,shahrzadmn/skia,qrealka/skia-hc,google/skia,MarshedOut/android_external_skia,UBERMALLOW/external_skia,pcwalton/skia,MinimalOS-AOSP/platform_external_skia,todotodoo/skia,TeamTwisted/external_skia,Hikari-no-Tenshi/android_external_skia,ominux/skia,UBERMALLOW/external_skia,Jichao/skia,rubenvb/skia,AOSP-YU/platform_external_skia,AOSPB/external_skia,AOSP-YU/platform_external_skia,qrealka/skia-hc,HalCanary/skia-hc,google/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,Infinitive-OS/platform_external_skia,AOSPB/external_skia,AOSP-YU/platform_external_skia,MonkeyZZZZ/platform_external_skia,MonkeyZZZZ/platform_external_skia,shahrzadmn/skia,vanish87/skia,UBERMALLOW/external_skia,YUPlayGodDev/platform_external_skia,MinimalOS-AOSP/platform_external_skia,google/skia,geekboxzone/mmallow_external_skia,rubenvb/skia,AOSPB/external_skia,MinimalOS-AOSP/platform_external_skia,nfxosp/platform_external_skia,w3nd1go/android_external_skia,nfxosp/platform_external_skia,rubenvb/skia,todotodoo/skia,UBERMALLOW/external_skia,nfxosp/platform_external_skia,nvoron23/skia,MonkeyZZZZ/platform_external_skia,BrokenROM/external_skia,Jichao/skia,aosp-mirror/platform_external_skia,invisiblek/android_external_skia,nvoron23/skia,BrokenROM/external_skia,Hikari-no-Tenshi/android_external_skia,vanish87/skia,AOSP-YU/platform_external_skia,noselhq/skia,HalCanary/skia-hc,invisiblek/android_external_skia,VRToxin-AOSP/android_external_skia,noselhq/skia,MarshedOut/android_external_skia,PAC-ROM/android_external_skia,TeamExodus/external_skia,rubenvb/skia,TeamExodus/external_skia,tmpvar/skia.cc,TeamTwisted/external_skia,MarshedOut/android_external_skia,nfxosp/platform_external_skia,spezi77/android_external_skia,ominux/skia,geekboxzone/mmallow_external_skia,VRToxin-AOSP/android_external_skia,timduru/platform-external-skia,todotodoo/skia,BrokenROM/external_skia,geekboxzone/mmallow_external_skia,google/skia,shahrzadmn/skia,MinimalOS-AOSP/platform_external_skia,vanish87/skia,geekboxzone/mmallow_external_skia,Infinitive-OS/platform_external_skia,noselhq/skia,aosp-mirror/platform_external_skia,Jichao/skia,OneRom/external_skia,rubenvb/skia,TeamTwisted/external_skia,w3nd1go/android_external_skia,VRToxin-AOSP/android_external_skia,google/skia,TeamTwisted/external_skia,Jichao/skia,Jichao/skia,Infinitive-OS/platform_external_skia,VRToxin-AOSP/android_external_skia,vanish87/skia,AOSP-YU/platform_external_skia,nfxosp/platform_external_skia,tmpvar/skia.cc,invisiblek/android_external_skia,nvoron23/skia,MonkeyZZZZ/platform_external_skia,invisiblek/android_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,timduru/platform-external-skia,AOSPB/external_skia,OneRom/external_skia,tmpvar/skia.cc,invisiblek/android_external_skia,BrokenROM/external_skia,tmpvar/skia.cc,w3nd1go/android_external_skia,w3nd1go/android_external_skia,Infinitive-OS/platform_external_skia,MinimalOS-AOSP/platform_external_skia,tmpvar/skia.cc,Hikari-no-Tenshi/android_external_skia,geekboxzone/mmallow_external_skia,HalCanary/skia-hc,qrealka/skia-hc,boulzordev/android_external_skia,HalCanary/skia-hc,nvoron23/skia,pcwalton/skia,todotodoo/skia,w3nd1go/android_external_skia,TeamTwisted/external_skia,shahrzadmn/skia,UBERMALLOW/external_skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,google/skia,noselhq/skia,spezi77/android_external_skia,YUPlayGodDev/platform_external_skia,Jichao/skia,timduru/platform-external-skia,noselhq/skia,HalCanary/skia-hc,OneRom/external_skia,VRToxin-AOSP/android_external_skia,google/skia,invisiblek/android_external_skia,MonkeyZZZZ/platform_external_skia,YUPlayGodDev/platform_external_skia,UBERMALLOW/external_skia,invisiblek/android_external_skia,tmpvar/skia.cc,ominux/skia,boulzordev/android_external_skia,OneRom/external_skia,TeamExodus/external_skia,rubenvb/skia,nvoron23/skia,pcwalton/skia,AOSPB/external_skia,Jichao/skia,aosp-mirror/platform_external_skia,nfxosp/platform_external_skia,w3nd1go/android_external_skia,w3nd1go/android_external_skia,vanish87/skia,nvoron23/skia,vanish87/skia,MarshedOut/android_external_skia,AOSPB/external_skia,noselhq/skia,MarshedOut/android_external_skia,Infinitive-OS/platform_external_skia,MinimalOS-AOSP/platform_external_skia,YUPlayGodDev/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,boulzordev/android_external_skia,aosp-mirror/platform_external_skia,todotodoo/skia,YUPlayGodDev/platform_external_skia,MinimalOS-AOSP/platform_external_skia,noselhq/skia,rubenvb/skia,noselhq/skia,TeamExodus/external_skia,MonkeyZZZZ/platform_external_skia,vanish87/skia,ominux/skia,PAC-ROM/android_external_skia,shahrzadmn/skia,qrealka/skia-hc,rubenvb/skia,google/skia,boulzordev/android_external_skia,TeamExodus/external_skia,AOSPB/external_skia,Infinitive-OS/platform_external_skia,TeamExodus/external_skia,pcwalton/skia,ominux/skia,tmpvar/skia.cc,AOSP-YU/platform_external_skia,AOSPB/external_skia,YUPlayGodDev/platform_external_skia,AOSPB/external_skia,spezi77/android_external_skia,shahrzadmn/skia,TeamExodus/external_skia,tmpvar/skia.cc,PAC-ROM/android_external_skia,vanish87/skia,VRToxin-AOSP/android_external_skia,MarshedOut/android_external_skia,shahrzadmn/skia,rubenvb/skia,qrealka/skia-hc,YUPlayGodDev/platform_external_skia,aosp-mirror/platform_external_skia,OneRom/external_skia