Remove Image unused and keep is per image instead of per database.

[DatKyle]

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Describe the bug When running the command: Remove-DcnImage -unused -keep 1 I would expect the command to remove unused images and keep the most recent image for each database. However, removes all unused and keeps the most recent image.

For example, I have 3 database images created on 1/7 and generate a new image for each database on 2/7. This gives me the below table:

ImageID	Database	Used?	Created
1	Db1	unused	1/7/2021
4	Db1	unused	2/7/2021
2	Db2	unused	1/7/2021
5	Db2	unused	2/7/2021
3	Db3	unused	1/7/2021
6	Db3	unused	2/7/2021

When you run the above command it would remove all images, leaving only 1 image (ImageID 6). I would expect it to only remove the oldest image per database, leaving us with ImageID 4, 5, and 6.

Is this intended? Are you meant to specify the database when using -unused -keep [x]?

I'm using dbaclone version: 0.10.38