Need way to get ALL members of group

[DennisSmolek]

Looking at the groups functions we already have groups_get_groups_admins, groups_get_groups_mods, and groups_get_group_members.

Logically you would assume get members would return everyone even the admins/mods but it doesnt.
Analyzing I notice it calls get_all_for_group from the group class which has parameters to exclude mods/admins by default.

Even groups_get_group_members having access to those parameters would be better.

Of course if the preferred method is to just call get_all_for_group disregard this....

[chrisclayton]

I suggest we add all of the parameters, like in the above attachment (not sure why the first one didn't work.)

[boonebgorges]

(In [6711]) Allow groups_get_group_members() to have access to all params of wrapped method

Fixes #4753

Props chrisclayton

Adds documentation for groups_get_group_members()