Fix an issue with URIs missing trailing slashes, like "/maniphest"

Summary:
In D3144, I made us look in application maps to find routing rules. However, we don't process all the maps when we 404 and try to do a "/" redirect. Process all of the maps.

Additionally, in D3146 I made the menu items application-driven. However, some pages (like 404) don't have a controller. Drop the requirement that the controller be nonnull.

Test Plan:

• Visited "/maniphest", got a redirect after this patch.
• Visited "/asldknfalksfn", got a 404 after this patch.

Reviewers: davidreuss, vrana, btrahan

Reviewed By: davidreuss

CC: aran

Maniphest Tasks: T1607

Differential Revision: https://secure.phabricator.com/D3158