Support tagging.

[RokeJulianLockhart]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.
• I optionally donated to support the Fossify mission.

Feature description

A one-to-many correspondence, possible to combine and exclude when filtering, for all inodes (files and directories primarily, although I've no qualms if it happens to introduce the ability to manage them for symbolic links too, for instance). Relevantly, https://apps.kde.org/en-gb/dolphin/, a file manager, manages tags for inodes using https://wiki.archlinux.org/title/Extended_attributes#File_systems.

Why do you want this feature?

Hierarchical directories are not adequate for complex file organization, because they fill the purpose of separation rather than organization - that is, files with identical names but which serve different purposes should be hierarchically separated, but in all other instances tags serve the purpose of organization significantly better.

Additional information

FossifyOrg/General-Discussion#127 (comment)