Support subtypes in Projects

Summary:
Ref T13242. See PHI1039. Maniphest subtypes generally seem to be working well. I designed them as a general capability that might be extended to other `EditEngine` objects later, and PHI1039 describes a situation where extending subtypes to projects would give us some reasonable tools.

(Some installs also already use icons/colors as a sort of lightweight version of subtypes, so I believe this is generally useful capability.)

Some of this is a little bit copy-pasted and could probably be shared, but I'd like to wait a bit longer before merging it. For example, both configs have exactly the same structure right now, but Projects should possibly have some different flags (for example: to disable creating subprojects / milestones).

This implementation is pretty basic for now: notably, subprojects/milestones don't get the nice "choose from among subtype forms" treatment that tasks do. If this ends up being part of a solution to PHI1039, I'd plan to fill that in later on.

Test Plan: Defined multiple subtypes, created subtype forms, created projects with appropriate subtypes. Filtered them by subtype. Saw subtype information on list/detail views.

Reviewers: amckinley

Reviewed By: amckinley

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13242

Differential Revision: https://secure.phabricator.com/D20040

src/applications/project/controller/PhabricatorProjectProfileController.php

@@ -51,6 +51,12 @@ final class PhabricatorProjectProfileController
     $watch_action = $this->renderWatchAction($project);
     $header->addActionLink($watch_action);
 
+    $subtype = $project->newSubtypeObject();
+    if ($subtype && $subtype->hasTagView()) {
+      $subtype_tag = $subtype->newTagView();
+      $header->addTag($subtype_tag);
+    }
+
     $milestone_list = $this->buildMilestoneList($project);
     $subproject_list = $this->buildSubprojectList($project);