R1:26944e28766a

Expose all LDAP configuration options in the web UI

Summary: Ref T1536. Love me some LDAP.

Test Plan: Viewed and edited form. Looked through transactions.

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran

Maniphest Tasks: T1536

Differential Revision: https://secure.phabricator.com/D6227