Started work on API token controls

- Added access-api permission.
- Started user profile UI work.
- Created database table and model for tokens.
- Fixed incorrect templates down migration :(

app/Api/ApiToken.php

@@ -0,0 +1,9 @@
+<?php namespace BookStack\Api;
+
+use Illuminate\Database\Eloquent\Model;
+
+class ApiToken extends Model
+{
+    protected $fillable = ['name', 'expires_at'];
+
+}