[keycloak-dev] Client scopes PR rebased, Documentation added

[Marek Posolda]

I've did a rebase of client scopes PR [1] against latest master. Also 
did the documentation for it in the PR [2] .

Anyone has a time to review? TBH I hope it's sorted soon as it changes 
291 files, so there is quite a chance for the conflict with every other 
PR send. And rebasing (which I already did 2 or 3 times) is quite a pain ;)

[1] https://github.com/keycloak/keycloak/pull/5076
[2] https://github.com/keycloak/keycloak-documentation/pull/389

Marek