feat(ui): (optional) Protect starred images from accidental deletion

[FloeHetling]

Summary

• new settings option: "Protect starred images"
• when protection is enabled, following features will be active:

• there will be impossible to delete an image with star mark. If "Confirm on delete" is enabled, a warning toast will appear on said attempt (silent otherwise)
• upon attempting to use "Delete Board and Images" option, additional confirmation will be issued if said board has at least one image with star mark
• upon attempting to delete a group selected of images, images marked with Star will not be touched and a toast about protection status will be thrown if "Confirm on delete" is enabled (silent otherwise)
• same behavior should be expected from "Delete All Uncategorized Images" option.

Related Issues / Discussions

Following this QoL plan from @hipsterusername (Discord message link)

QA Instructions

Careful. This test implies all of the images can or will be eventually lost. For safety of your artwork, consider using testing environment

• have some images to start test with, 10x should be enough.
• enable the "Protect starred images" option in your app Settings
• mark 2 images, select 3 images, 2 of which are marked and 1 is not. Press the Delete key or use Delete icon in viewer. Expected behavior: one unmarked artwork should be deleted
• create a new board and move those 2 marked images there. Add 1 unmarked image. Attempt to delete that board using "Delete Board and Images" option. Expected behavior: additional confirmation should be issued about deleting the board with starred images. Upon agreeing, the board must be gone with all of 3 images.
• you can test verbosity of alerts on six images that are left. "Confirm on delete" option should warn you if you are attempting to delete a starred image by issuing a toast. Leave at least 2 images - one with the Star mark and one without.
• use "Delete All Uncategorized Images" from "Uncategorized" board context menu. Confirm the deletion. Expected behavior: the starred image should be left untouched.

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Tests added / updated (if applicable)
• Documentation added / updated (if applicable)
• Updated What's New copy (if doing a release after this PR)