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/Discussions/DiscussionsServiceProvider.php

@@ -0,0 +1,74 @@
+<?php namespace Flarum\Core\Discussions;
+
+use Flarum\Core\Search\GambitManager;
+use Flarum\Core\Users\User;
+use Flarum\Support\ServiceProvider;
+use Flarum\Extend;
+use Illuminate\Contracts\Container\Container;
+
+class DiscussionsServiceProvider extends ServiceProvider
+{
+    /**
+     * Bootstrap the application events.
+     *
+     * @return void
+     */
+    public function boot()
+    {
+        $this->extend([
+            new Extend\EventSubscriber('Flarum\Core\Discussions\Listeners\DiscussionMetadataUpdater')
+        ]);
+
+        Discussion::allow('*', function (Discussion $discussion, User $user, $action) {
+            return $user->hasPermission('discussion.'.$action) ?: null;
+        });
+
+        // Allow a user to rename their own discussion.
+        Discussion::allow('rename', function (Discussion $discussion, User $user) {
+            return $discussion->start_user_id == $user->id ?: null;
+            // TODO: add limitations to time etc. according to a config setting
+        });
+
+        Discussion::allow('delete', function (Discussion $discussion, User $user) {
+            return $discussion->start_user_id == $user->id && $discussion->participants_count == 1 ?: null;
+            // TODO: add limitations to time etc. according to a config setting
+        });
+    }
+
+    /**
+     * Register the service provider.
+     *
+     * @return void
+     */
+    public function register()
+    {
+        $this->app->bind(
+            'Flarum\Core\Discussions\DiscussionRepositoryInterface',
+            'Flarum\Core\Discussions\EloquentDiscussionRepository'
+        );
+
+        $this->app->bind(
+            'Flarum\Core\Discussions\Search\Fulltext\DriverInterface',
+            'Flarum\Core\Discussions\Search\Fulltext\MySqlFulltextDriver'
+        );
+
+        $this->app->instance('flarum.discussionGambits', [
+            'Flarum\Core\Discussions\Search\Gambits\AuthorGambit',
+            'Flarum\Core\Discussions\Search\Gambits\UnreadGambit'
+        ]);
+
+        $this->app->when('Flarum\Core\Discussions\Search\DiscussionSearcher')
+            ->needs('Flarum\Core\Search\GambitManager')
+            ->give(function (Container $app) {
+                $gambits = new GambitManager($app);
+
+                foreach ($app->make('flarum.discussionGambits') as $gambit) {
+                    $gambits->add($gambit);
+                }
+
+                $gambits->setFulltextGambit('Flarum\Core\Discussions\Search\Gambits\FulltextGambit');
+
+                return $gambits;
+            });
+    }
+}