Option to delete only raw (or only jpg)

[r41d]

Setup (please complete the following information):

• Geeqie version [geeqie --version]: Geeqie 2.6.1 GTK3

Describe your feature request
The automatic grouping of a jpg and a corresponding raw file is one of the key features of geeqie. (At least for me. It's a bit sad to see that so little software can do this.) This features also allows to delete a raw and jpg file in one step which is also very handy.
But when sorting through files there can be situations where the user only wants to keep the jpg because (s)he likes the picture but is sure that (s)he doesn't want to edit the raw and wants to save on disk space since the raw is many times larger.
There's already the option to disable file grouping but that:

• is another step encompassing 2 more mouse clicks and
• leads to the raw file appearing at the very top of the file list where it needs to be located, deleted and then the use needs to find the place in the middle where (s)he left off, which is cumbersome.
  Vice versa there can also be situations where only the raw should be kept when the user is 99% sure that postprocess should happen in the future (though that case is probably much rarer).

Additional context
The option to only delete the raw file of a grouping could be added to the right-click context menu of an image or a selection of images, e.g. right below "Delete selection".
A new keyboard shortcut (one for delete raw and delete jpg each) would complement the feature.

[caclark]

My immediate thoughts about filtering:

If you are working with a single file, switching to List View lets you choose any part of a group.

If you go to Select/Show File Filter you can put a regex in the filter box.

This seems useful, except that it does not seem to work for the first extension in a group
e.g. jpg+dng+xmp

If either dng or xmp are in the filter, the results are as I expect - not so if jpg is in the filter.

There is also a drop-down to filter by Class. That looks like it is filtering on the first file type in a group, but displays all the files in the group. Maybe that is not correct.