Add backers and sponsors from Open Collective (#1281)
Add backers and sponsors from Open Collective (#1281)

This is for your open collective backers and sponsors to appear directly on your README. 
see how it'll look [here](https://github.com/apex/apex#backers)
[More info](https://github.com/opencollective/opencollective/wiki/Github-banner)

Also add badges on top.
notklaatu/grav,JamesPan/gravbox,tomzx/blog.tomrochette.com,JamesPan/gravbox,Sommerregen/grav,joeyhenricks/a-broke-vegan,joeyhenricks/a-broke-vegan,dimayakovlev/grav,JamesPan/gravbox,stell/grav,shortsofia/testesitegrav.github.io,tomzx/blog.tomrochette.com,Vivalldi/grav,ccardinaux/grav-test,tomzx/blog.tomrochette.com,webuxr/iamrs,dimayakovlev/grav,getgrav/grav,notklaatu/grav,tomzx/blog.tomrochette.com,JamesPan/gravbox,getgrav/grav,Vivalldi/grav