Move member/watch actions to "Members/Watchers" page

Summary:
Ref T10054. This tries to make the members page a bit more consistent and provide hints to users about subproject/milestone membership rules. In particular:

  - You now join, leave, watch, unwatch, add and remove members, and lock and unlock membership from the members screen.
  - We now explain the membership rule for the project on this screen. There are currently four rules:
    - Normal Project: Join/leave normally.
    - Parent Project: Uses subprojects to determine members.
    - Milestone: Uses parent project to determine members.
    - Locked: Membership is locked.
    - (Future) Imported from LDAP/other external sources: Membership is determined by something else.

Test Plan: {F1064878}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10054

Differential Revision: https://secure.phabricator.com/D15059

src/applications/project/controller/PhabricatorProjectMembersAddController.php

@@ -0,0 +1,72 @@
+<?php
+
+final class PhabricatorProjectMembersAddController
+  extends PhabricatorProjectController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $request->getViewer();
+    $id = $request->getURIData('id');
+
+    $project = id(new PhabricatorProjectQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($id))
+      ->requireCapabilities(
+        array(
+          PhabricatorPolicyCapability::CAN_VIEW,
+          PhabricatorPolicyCapability::CAN_EDIT,
+        ))
+      ->executeOne();
+    if (!$project) {
+      return new Aphront404Response();
+    }
+
+    $this->setProject($project);
+
+    if (!$project->supportsEditMembers()) {
+      return new Aphront404Response();
+    }
+
+    $done_uri = "/project/members/{$id}/";
+
+    if ($request->isFormPost()) {
+      $member_phids = $request->getArr('memberPHIDs');
+
+      $type_member = PhabricatorProjectProjectHasMemberEdgeType::EDGECONST;
+
+      $xactions = array();
+
+      $xactions[] = id(new PhabricatorProjectTransaction())
+        ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
+        ->setMetadataValue('edge:type', $type_member)
+        ->setNewValue(
+          array(
+            '+' => array_fuse($member_phids),
+          ));
+
+      $editor = id(new PhabricatorProjectTransactionEditor($project))
+        ->setActor($viewer)
+        ->setContentSourceFromRequest($request)
+        ->setContinueOnNoEffect(true)
+        ->setContinueOnMissingFields(true)
+        ->applyTransactions($project, $xactions);
+
+      return id(new AphrontRedirectResponse())
+        ->setURI($done_uri);
+    }
+
+    $form = id(new AphrontFormView())
+      ->setUser($viewer)
+      ->appendControl(
+        id(new AphrontFormTokenizerControl())
+          ->setName('memberPHIDs')
+          ->setLabel(pht('Members'))
+          ->setDatasource(new PhabricatorPeopleDatasource()));
+
+    return $this->newDialog()
+      ->setTitle(pht('Add Members'))
+      ->appendForm($form)
+      ->addCancelButton($done_uri)
+      ->addSubmitButton(pht('Add Members'));
+  }
+
+}