Massive refactor

- Use contextual namespaces within Flarum\Core
- Clean up and docblock everything
- Refactor Activity/Notification blueprint stuff
- Refactor Formatter stuff
- Refactor Search stuff
- Upgrade to JSON-API 1.0
- Removed “addedPosts” and “removedPosts” relationships from discussion
API. This was used for adding/removing event posts after renaming a
discussion etc. Instead we should make an additional request to get all
new posts

Todo:
- Fix Extenders and extensions
- Get rid of repository interfaces
- Fix other bugs I’ve inevitably introduced

src/Core/Users/Commands/DeleteUserHandler.php

@@ -0,0 +1,44 @@
+<?php namespace Flarum\Core\Users\Commands;
+
+use Flarum\Core\Users\User;
+use Flarum\Core\Users\UserRepositoryInterface;
+use Flarum\Core\Users\Events\UserWillBeDeleted;
+use Flarum\Core\Support\DispatchesEvents;
+
+class DeleteUserHandler
+{
+    use DispatchesEvents;
+
+    /**
+     * @var UserRepositoryInterface
+     */
+    protected $users;
+
+    /**
+     * @param UserRepositoryInterface $users
+     */
+    public function __construct(UserRepositoryInterface $users)
+    {
+        $this->users = $users;
+    }
+
+    /**
+     * @param DeleteUser $command
+     * @return User
+     * @throws \Flarum\Core\Exceptions\PermissionDeniedException
+     */
+    public function handle(DeleteUser $command)
+    {
+        $actor = $command->actor;
+        $user = $this->users->findOrFail($command->userId, $actor);
+
+        $user->assertCan($actor, 'delete');
+
+        event(new UserWillBeDeleted($user, $actor, $command->data));
+
+        $user->delete();
+        $this->dispatchEventsFor($user);
+
+        return $user;
+    }
+}