[MU4 Issue] List of recent files grows infinitely

Describe the bug
The list of recent files grows infinitely; it can become unlimitedly long.

Expected behavior
@Tantacrul / @bkunda, what shall we do?

Possible solutions:

• limit by number, for example max 100 recent files
• limit by modified date, for example max 1 year since modified. But actually, this is not an option, because it would imply that a file that is opened without modifying and last modified more than 1 year ago will not appear in the list.
• limit by opened date, but that would require storing the opening dates in the list of recent files, because not all operating systems support "opened" date.

Of course, we don't want to set the limit too low, because a filled home page looks 100x nicer than with just a few scores. On the other hand, in the menu bar > File > Open recent, it doesn't look very nice to have a super long list. Of course, we can cut the File > Open recent list at 10 files and let the Home list grow longer, but I'm not sure whether that's a good idea, and we'll need to limit the list anyway, otherwise we waste kilobytes or eventually megabytes of disk space with just the list of recent files.