Add remove checkbox to FileType (StorageBundle)

Test NOK: see attachment.

Steps-to-reproduce:

• Upload new image

• Use the 'remove' checkbox, click save

• Now delete the item (the item still exists, although the image itself is removed with the remove checkbox)

• Error.

Can you re-open this issue? I first tested this issue, and everything seemed fine, later I discovered this error.

Look's goooood! We already merged it last week. I forgot to accept it in Jira.