When creating a repository in Diffusion, prompt for "Create" or "Import" first

Summary:
Ref T2230. This will need some more refinement, but basically it adds a "Create" vs "Import" step before we go through the paged workflow.

  - If you choose "Create", we skip the remote URI / auth stuff, and then set the "hosted" flag.
  - If you choose "Import", we do what we do now.

Test Plan: Created and imported repos.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2230

Differential Revision: https://secure.phabricator.com/D7475

src/applications/diffusion/controller/DiffusionRepositoryListController.php

@@ -107,8 +107,8 @@ final class DiffusionRepositoryListController extends DiffusionController
 
     $crumbs->addAction(
       id(new PHUIListItemView())
-        ->setName(pht('Import Repository'))
-        ->setHref($this->getApplicationURI('/create/'))
+        ->setName(pht('New Repository'))
+        ->setHref($this->getApplicationURI('new/'))
         ->setDisabled(!$can_create)
         ->setIcon('create'));