Update readme
Update readme

- Link to prod instance docs / sandbox
- Remove outdated API spec

d00rman/restbase,milimetric/restbase,cscott/restbase,inverno/restbase,Pchelolo/restbase,eevans/restbase,milimetric/restbase,cscott/restbase,eevans/restbase,d00rman/restbase,Krenair/restbase,wikimedia/hyperswitch,physikerwelt/restbase,physikerwelt/restbase,wikimedia/restbase,wikimedia/mediawiki-services-restbase,gwicke/restbase,Pchelolo/restbase,inverno/restbase,gwicke/restbase,Krenair/restbase,wikimedia/mediawiki-services-restbase,wikimedia/restbase