Quicker editing of shepherding group families

We've added the ability to add and remove families from a shepherding group directly from the group page. Previously the only way to change this was to edit this on a person's page in the "People" section.

Now when you (as an administrator) visit a shepherding group page, you'll see a new "Edit families" option in the three-dot dropdown menu. From there you'll see a list of all the active families within your church, and can add or remove them from that group.

Note, there is a "Remove families from existing shepherding groups when adding" option in this dialog, which will automatically remove a family from all their existing shepherding groups. This can be really helpful if families only ever exist in one shepherding group in your church.