Improve file trash handling

[klawr]

Problem Description
There is at the moment no way of seeing the trash, empying it or restoring files.

Proposed Solution
Implement Get, Restore and Delete for the trashs in the respective subdirectories.
Add frontend to see trash, empty it and read.

Possible Alternative Approaches
The handling of files in trash can be done via the admin using the file management in the background.
However this should be made available to the user, hence this feature request.

Additional Context
First try was undertaken but using a separate trash beside the fileHandles does not really work for the updates.
Using this method needs a rewrite or some store subscribers for that.
The trash should not be this intrusive into the current scheme. Maybe a simpler solution is possible.