Add `all_available` argument to `Resolvers::GroupsResolver`

Background

For #502486 (closed) we want to set the all_available param to false so public groups you are not a member of are not returned.

Proposal

Add a all_available argument to Resolvers::GroupsResolver. It should use the same defaults as the similar REST API endpoint. It looks like the GroupsFinder already supports this argument.

Implementation guide

• Add the field so it can be used as an argument and pass it to the Finder.
• Find out how we can describe the default behaviour in GraphQL terms (see argument )