Improve some column behaviors for Milestone/Subproject columns

Summary:
Ref T10010.

  - Don't allow milestones to be reordered.
  - Hide phantom subproject columns when reodrering.
  - Don't allow subproject/milestone columns to be renamed.
  - Force milestones to be ordered at the end, and in the correct order.
  - Add some missing crumbs.

Test Plan: Reordered columns, renamed columns, made a new column, viewed column details.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10010

Differential Revision: https://secure.phabricator.com/D15183

src/applications/project/engine/PhabricatorBoardLayoutEngine.php

@@ -317,7 +317,7 @@ final class PhabricatorBoardLayoutEngine extends Phobject {
       ->setViewer($viewer)
       ->withProjectPHIDs(array_keys($boards))
       ->execute();
-    $columns = msort($columns, 'getSequence');
+    $columns = msort($columns, 'getOrderingKey');
     $columns = mpull($columns, null, 'getPHID');
 
     $need_children = array();
@@ -368,6 +368,8 @@ final class PhabricatorBoardLayoutEngine extends Phobject {
         }
       }
 
+      $board_columns = msort($board_columns, 'getOrderingKey');
+
       $columns[$board_phid] = $board_columns;
     }