Customize sorting for each column individually

[FenPhoenix]

While working on improving the sorting behavior of the FMs list columns, I realized that there could be multiple different ways you might want to sort a column. For instance, for the rating column, it could be much nicer to sort only the rated rows, and leave all unrated rows at the bottom at all times. That way you don't have to get a sea of empty rows at the top and then scroll all the way down to see your ratings. But then again, it could also sometimes be desirable to have that behavior if you're interested in seeing which FMs you haven't yet rated in particular. Or, as in the Last Played column, you might want to sort in reverse first because it makes more sense to have the most recent times at the top, but then again sorting normally is "more logical". We could have a Settings section where you can set these kind of options per-column maybe. We could also add a submenu to the column header context menu where you could sort a certain way just that once.

[Skibicki]

I like to preserve date sorting.
Example: Sort by Date, then sort by Author. Date sorting is kept.