Put rel="noreferrer" on all nonlocal links

Summary:
Ref T4342. By default, insert `rel="noreferrer"` for links. We do not insert this if:

  - The caller provided an explicit "rel" attribute.
  - We recognize the link as an anchor ("#comment-2"), or as local to the current domain ("/path/to/resource").

Otherwise, add it in all cases.

Test Plan: Added and executed unit tests. (The javascript stuff which was touched a little bit has a pile of tests already, too.)

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4342

Differential Revision: https://secure.phabricator.com/D8711
Add an "Always Search" flag to the libphutil LDAP adapter

Summary:
Ref T3208. This adds a flag which acts like the old "Search First" flag did, more or less, probably. LDAP?

Specifically, the issue at heart here is that some LDAP servers require totally uncredentialed binds, some require "anonymous" binds (not sure if this is a term of art or if whoever contributed the first LDAP patch made it up), and some require full DN binds. This flag lets us distinguish between the "full DN" and "completely uncredentialed" use cases, both of which have no "anonymous" credentials.

Test Plan: It compiles!

Reviewers: Firehed

Reviewed By: Firehed

Subscribers: epriestley

Maniphest Tasks: T3208

Differential Revision: https://secure.phabricator.com/D8722