* Add profile.groups.read api endpoint

* Remove metadata from list groups api call

Rather than relying on the token of the logged in user being returned
as extra metadata from the list groups api call, simple use the profile
userid from the data store to determine whether a use is logged in or not.

* Add util/groups module with combineGroups helper

This will be used when the community-groups feature flag is set, to combine
groups from the groups list and profile groups endpoints.

* Add tests for util groups module

* Add tests for community-groups feature flag