add 'DmCommon\View\Helper\UserText' with pointer to DmMailerdmin Factory

this feels as a strange workaround right now - should be better way to solve the problem as I did to get things running.

After installing a fresh copy of dermailer and without data inside the db, I got many exceptions calling for 'DmCommon\View\Helper\UserText' [the tinyMce Module Factory\Controller\Message was causing the exception]. 

With data inside and without my "fix" I now get:

```Catchable fatal error: Argument 4 passed to DmMailerAdmin\Controller\CampaignController::__construct() must be an instance of DmCommon\View\Helper\UserText, instance of DmCommon\Service\ErrorHandler given, called in /Sites/_git/dermailer/vendor/peteraba/dm-tinymce/src/DmTinymce/Factory/Controller/Campaign.php on line 49 and defined in /Sites/_git/dermailer/vendor/peteraba/dm-maileradmin/src/DmMailerAdmin/Controller/CampaignController.php on line 57```

This userText view plugin is used by different modules through different factories - so I assume it gets called through code before view layer? So perhaps it is more then a view helper? Did not dive into code to understand it well. Perhaps you can give short description, how this setup is intended? So, perhaps I can provide a better fix for my problems with that plugin.

Regards


So this should actually go into dm-maileradmin I think.