Issue: Change global wiki header switch to content type based switches

There should also be an "Added via admin panel" option. This way we can let admins use the Content > Integration screen to create a header e.g. on a specific profile, but if "Profiles" is unchecked, then there are no controls to create a new header when visiting a profile that doesn't have one.

For the "Profiles" option specifically, I think there should be a Usergroup setting, so that only members of specific Usergroups can have a header. While it can be cool to let a member feature a wiki page on their profile, this feature was created mainly to show wiki biographies of notable members. A usergroup setting would allow us to say who is notable and who is not.

For clarification of "Wiki content container", I suppose that you mean:

For each content-type, have additional options for integration containers that would be supported by that type.
For example, it should be possible to show a profile integration as either a header OR a tab, but it wouldn't make sense to show a thread integration as a tab. This capability awaits a fix for the "Position" regression, however.

The global "Allow Wiki Content Integration" setting has been changed to checkboxes for each integrate-type that exists in the controller/ui/integrate directory. The query will still be added for all types, regardless of this setting, because there is an appropriate exception for integrations added by admins.

There is now a Usergroup Permission (in the platform's regular Usergroup Permissions page) that controls what Usergroups can and can't have integrations on their profiles. Allow this for admin or staff users, if you have staff bios in your wiki; or allow this for anyone if you want to let users feature their favorite wiki page on their profile.

Marking this feature as Implemented.