Introduce Member Types API.
BuddyPress member types are akin to WordPress's custom post types. Developers
can use bp_register_member_type() to register their types with BuddyPress,
and BP will automatically provide a number of pieces of functionality:
- Mechanisms for storing and fetching member types (as a WP taxonomy term), with full cache support.
- A 'member_type' argument for the
bp_has_members()/BP_User_Query stack, which allows filtering member loops by member type.
- Admin UI for changing member types on Dashboard > Users > Community Profile (appears when member types have been registered).
We'll continue to build out more core member type functionality in future
versions of BuddyPress. In the meantime, this is a good starting point for BP
site implementations to have a shared infrastructure for storing and retrieving
this data.
See #6006.