add specific links to 'adding functionality' intro
add specific links to 'adding functionality' intro

add links directly to the tabs for plugins and themes on getgrav.org. The first time I loaded the main downloads page I didn't see the plugins/themes tabs because I immediately started scrolling down. It might be worth adding to the bottom of that main page a quick line to the tune of "Looking for plugins or themes? Click here or here."
lennerd/grav,Silwereth/grav,webuxr/iamrs,getgrav/grav,notklaatu/grav,tomzx/blog.tomrochette.com,Sommerregen/grav,ccardinaux/grav-test,Pumpapa/lucaswalters.nl,Pumpapa/jacinthawalters.nl,notklaatu/grav,JamesPan/gravbox,dimayakovlev/grav,sylvestrelucia/grav,undesign/undesign.github.io,shortsofia/testesitegrav.github.io,tomzx/blog.tomrochette.com,tomzx/blog.tomrochette.com,toovy/grav,undesign/undesign.github.io,iMoonThailand/grav,joeyhenricks/a-broke-vegan,Vivalldi/grav,userfrosting/learn,userfrosting/learn,Pumpapa/lucaswalters.nl,Pumpapa/lucaswalters.nl,Pumpapa/chriswalters.nl,tomzx/blog.tomrochette.com,Vivalldi/grav,stell/grav,joeyhenricks/a-broke-vegan,dimayakovlev/grav,tcsizmadia/grav,TheHiddenHaku/alessiobottiroli-website-grav,gigago/grav,sylvestrelucia/grav,userfrosting/learn,userfrosting/learn,sylvestrelucia/grav,JamesPan/gravbox,getgrav/grav,toovy/grav,JamesPan/gravbox,sylvestrelucia/grav,JamesPan/gravbox