luci-base: expose system translations to JavaScript
luci-base: expose system translations to JavaScript

Add a new /admin/translations/ endpoint which exposes the loaded system
translations as JavaScript file.

Once referenced by <script>, the endpoint will create a `window.TR` object
containing the entire translation string table for use on the client side.

Signed-off-by: Jo-Philipp Wich <bd73d35759d75cc215150d1bbc94f1b1078bee01@mein.io>

rogerpueyo/luci,hnyman/luci,openwrt-es/openwrt-luci,artynet/luci,artynet/luci,Noltari/luci,nmav/luci,openwrt-es/openwrt-luci,Noltari/luci,openwrt/luci,nmav/luci,nmav/luci,tobiaswaldvogel/luci,tobiaswaldvogel/luci,tobiaswaldvogel/luci,openwrt/luci,openwrt/luci,rogerpueyo/luci,nmav/luci,rogerpueyo/luci,hnyman/luci,artynet/luci,nmav/luci,openwrt/luci,Noltari/luci,openwrt/luci,tobiaswaldvogel/luci,openwrt-es/openwrt-luci,Noltari/luci,Noltari/luci,hnyman/luci,rogerpueyo/luci,rogerpueyo/luci,nmav/luci,lbthomsen/openwrt-luci,lbthomsen/openwrt-luci,hnyman/luci,openwrt/luci,rogerpueyo/luci,Noltari/luci,Noltari/luci,lbthomsen/openwrt-luci,hnyman/luci,hnyman/luci,nmav/luci,Noltari/luci,artynet/luci,nmav/luci,tobiaswaldvogel/luci,openwrt-es/openwrt-luci,nmav/luci,lbthomsen/openwrt-luci,hnyman/luci,lbthomsen/openwrt-luci,openwrt-es/openwrt-luci,rogerpueyo/luci,lbthomsen/openwrt-luci,openwrt-es/openwrt-luci,hnyman/luci,lbthomsen/openwrt-luci,Noltari/luci,artynet/luci,artynet/luci,tobiaswaldvogel/luci,openwrt/luci,tobiaswaldvogel/luci,lbthomsen/openwrt-luci,rogerpueyo/luci,openwrt-es/openwrt-luci,artynet/luci,artynet/luci,tobiaswaldvogel/luci,openwrt-es/openwrt-luci,openwrt/luci,artynet/luci