Notification fs

In this PR, notify the user that the ```delete/chgrp``` of a MIF cannot happen if all the images composing the MIF aren't selected
This only works if the images are selected.
The error handling of the action (for example if a dataset is selected) will happen in another PR. see https://trac.openmicroscopy.org.uk/ome/ticket/10883
the dialog still requires a bit of TLC

To Test:
 * Import a lei file
 * Select an image composing the MIF.
 * Right click on delete.
 * A dialog should pop up. The delete action should not go ahead.
* Select the same image and another image not part of a MIF (e.g. jpeg)
* Only the second image should be deleted.

Repeat the same action for ``` chgrp```