Added basic system tests for markdown editor, Added extra test helpers

[bookstack] / resources / views / form / restriction-checkbox.blade.php

<label>
    <input value="true" id="{{$name}}[{{$role->id}}][{{$action}}]" type="checkbox" name="{{$name}}[{{$role->id}}][{{$action}}]"
           @if(old($name .'.'.$role->id.'.'.$action) || (!old() && isset($model) && $model->hasRestriction($role->id, $action))) checked="checked" @endif
    >
    {{ $label }}
</label>