Add console extender (#2057)

* Made the console command system extender-friendly

* Added console extender

* Added ConsoleTestCase to integration tests

* Added integration tests for console extender

* Marked event-based console extension system as deprecated

* Moved trimming command output of whitespace into superclass

* Renamed 'add' to 'command'

* Added special processing for laravel commands

* Code style fixes

* More style fixes

* Fixed $this->container

framework/core/src/Extend/Console.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extend;
+
+use Flarum\Extension\Extension;
+use Illuminate\Contracts\Container\Container;
+
+class Console implements ExtenderInterface
+{
+    protected $addCommands = [];
+
+    /**
+     * Add a command to the console.
+     *
+     * @param string $command ::class attribute of command class, which must extend Flarum\Console\AbstractCommand
+     */
+    public function command($command)
+    {
+        $this->addCommands[] = $command;
+
+        return $this;
+    }
+
+    public function extend(Container $container, Extension $extension = null)
+    {
+        $container->extend('flarum.console.commands', function ($existingCommands) {
+            return array_merge($existingCommands, $this->addCommands);
+        });
+    }
+}