Make "profile menu" configuration mostly work

Summary:
Ref T10054. This does a big chunk of the legwork to let users reconfigure profile menus (currently, just project menus).

This includes:

  - Editing builtin items (e.g., you can rename the default items).
  - Creating new items (for now, only links are available).

This does not yet include:

  - Hiding items.
  - Reordering items.
  - Lots of fancy types of items (dashboards, etc).
  - Any UI changes.
  - Documentation (does feature: TODO link for documentation).

Test Plan:
{F1060695}

{F1060696}

{F1060697}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10054

Differential Revision: https://secure.phabricator.com/D15010

src/applications/project/controller/PhabricatorProjectController.php

@@ -18,7 +18,10 @@ abstract class PhabricatorProjectController extends PhabricatorController {
     $viewer = $this->getViewer();
     $request = $this->getRequest();
 
-    $id = $request->getURIData('id');
+    $id = nonempty(
+      $request->getURIData('projectID'),
+      $request->getURIData('id'));
+
     $slug = $request->getURIData('slug');
 
     if ($slug) {