Add some Drydock documentation plus "Test Configuration" for repository automation

Summary:
Ref T182. Ref T9252.

  - Adds a "Test" repository operation that just runs `git status` to see if things work.
  - Adds a button for it in Edit Repository.
  - Shows operation status on the operation detail view to make this workflow work a little better.
  - Adds a lot of words. Words words words words.

Test Plan:
  - Tested repository operation.
  - Read words.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T182, T9252

Differential Revision: https://secure.phabricator.com/D14349

src/applications/diffusion/controller/DiffusionRepositoryEditMainController.php

@@ -688,6 +688,19 @@ final class DiffusionRepositoryEditMainController
         $this->getRepositoryControllerURI($repository, 'edit/automation/'));
     $view->addAction($edit);
 
+    $can_test = $repository->canPerformAutomation();
+
+    $test = id(new PhabricatorActionView())
+      ->setIcon('fa-gamepad')
+      ->setName(pht('Test Configuration'))
+      ->setWorkflow(true)
+      ->setDisabled(!$can_test)
+      ->setHref(
+        $this->getRepositoryControllerURI(
+          $repository,
+          'edit/testautomation/'));
+    $view->addAction($test);
+
     return $view;
   }