Added method to find all Datasets linked to a certain image
Added Multiple-Dataset warning dialog #11883

When the user wants to delete an image which is linked to multiple datasets a warning dialog will be shown, see trac #11883
Added empty method to NullOmeroPojoService to match OmeroDataService interface
Added comment, updated copyright date
Corrected copyright date
Warning dialog now shows information about the linked Datasets
Removed thumbnails from multiple dataset links warning dialog
Changed to a more performant database query
Just fixed a spelling error
Removed wrong import
Merge pull request #2160 from dominikl/delete_warning_develop

Warning dialog before deletion of linked images