Group status inactive/paused reason

So that metrics better reflect the situation, add a way to assign the reason for a group to be inactive in the group status. There are only 2 choices: Inactive, Active.

Maybe the [Group] is still meeting but not being updated or are away travelling.

This setting [reason for group on pause - inactive] could also disable the update needed flag.

This issue might relate to issue #777 where a new group is about to be formed but hasn't actually started (which would also be a good reason to have the ability to set the start date of a group).