groups_create_group() doesn't set total_member_count

[rogercoathup]

Groups created programmatically with groups_create_group() do not show in the Group Directory.

If called without a creator_id, the function sets up a default creator, but does not set total_member_count to 1 in the group meta table.

As a result, subsequent calls to construct the BP_Groups_Template fail to include the groups.

[boonebgorges]

It's always been this way, but I agree that it's kinda dumb. We should be doing this within the context of groups_create_group(). There shouldn't be backpat problems, because plugins currently doing it the old way will simply overwrite the total_member_count key.

[boonebgorges]

In 7172:

Set initial group metadata in groups_create_group() rather than action function

Groups created through the user interface have two pieces of metadata set in
groups_action_create_group(): the total_member_count and the last_activity.
(Both items are needed for newly created groups to show up in directories.)
However, the placement of these groups_update_groupmeta() calls - in what is
essentially a controller function - meant that groups created programatically
using groups_create_group() did not have their complete metadata set. Moving
the metadata setting into groups_create_group() means one less step for plugins
and other scripts that create groups programatically.

Fixes #4827

Props ericlewis, rogercoathup