Added clear activity/revision commands. Cleaned commands.

Added testing to cover each command.
Removed example laravel inspire command.
Standardised command names to be behind 'bookstack' naming.
In reference to #320.

app/Console/Commands/ClearActivity.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace BookStack\Console\Commands;
+
+use BookStack\Activity;
+use Illuminate\Console\Command;
+
+class ClearActivity extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'bookstack:clear-activity';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Clear user activity from the system';
+
+    protected $activity;
+
+    /**
+     * Create a new command instance.
+     *
+     * @param Activity $activity
+     */
+    public function __construct(Activity $activity)
+    {
+        $this->activity = $activity;
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $this->activity->newQuery()->truncate();
+        $this->comment('System activity cleared');
+    }
+}