Improve deletion of actions

As a user I want to be able to delete an action, no matter if there is a link between the action and an attachment. Once there is such a link, we want to delete it it as well (but the attachment should stay).

This affects mostly all actions:

• Generic device actions
• Generic platform actions
• Device software update actions
• Platform software update action
• Device Calibration Action (and there also deletion of the device property calibrations - bot no deletion of the device properties itself)
• ...