Groups: change Automatic grouping

[MartinKarim]

Description of Issue	Possible Solution	Warnings
Automatic grouping (e.g. by keywords is too complex)	Automatically create groups for every unique value of a BibTeX field; let the user change the field for grouping via dropdown at the top;	Users should not be able to manually add or remove groups in this tab;
Users need to be aware of the different grouping modes	use unique icon for automatic grouping	-

[AEgit]

Note, that this suggestion appears to imply that users can only see EITHER manual groups OR automatic ones. I personally do not use the automatic grouping feature, so I don't mind this, but I could see people wanting to be able to see both manual and automatic groups simultaneously.

[github-actions]

This issue has been inactive for half a year. Since JabRef is constantly evolving this issue may not be relevant any longer and it will be closed in two weeks if no further activity occurs.

As part of an effort to ensure that the JabRef team is focusing on important and valid issues, we would like to ask if you could update the issue if it still persists. This could be in the following form:

• If there has been a longer discussion, add a short summary of the most important points as a new comment (if not yet existing).
• Provide further steps or information on how to reproduce this issue.
• Upvote the initial post if you like to see it implemented soon. Votes are not the only metric that we use to determine the requests that are implemented, however, they do factor into our decision-making process.
• If all information is provided and still up-to-date, then just add a short comment that the issue is still relevant.

Thank you for your contribution!

[AtrusRiven]

I consider this an important step for UI usability and clarity. Should be linked with #4681 and #4682 in a "metaissue".

[AtrusRiven]

Is there planning on working on this? I don't know what the devs are planning but it could be merged with #4681 and #4682 (and other issues related to the topic?).

[koppor]

@AtrusRiven proposed three tabs at #4681 (comment). Thus, that issue is the more recent one. I close this to keep the number of opend issues low.