Provide organization to the authentication settings forms.
Review Request #8378 — Created Sept. 3, 2016 and submitted
The authentication settings forms have always just been a flat list of fields, without any real organization and, in some cases, no sane order. That made some settings forms, like for LDAP, a bit confusing. This change adds support for fieldsets for auth forms, and makes use of them for Active Directory, Standard Auth, and LDAP.
Visually and functionally tested each form. Counted the fields to make
sure that nothing went missing.