Create "favorites" and/or recent(s) for spawners

[TheDuckCow]

This was an awesome suggestion from the user feedback form. To quote:

"Add favourites. Like on Shift-A menu and then we go to mcprep>Favourites and then we find our favourites Mob,Players and items"

This seems pretty reasonable to do, and it could work across different spawners as well as the material generator. Having a favorites category for mobs is easy, will require some local storage. For other spawners, likely would need to be some tick box or other filter system. Likewise storing the most recent e.g. 5 could be quite useful.

This would also make the shift-A menus much more usable, if the favorites were listed first at the top (assuming they would have repeat entries, which is fine).

[StandingPadAnimations]

I've attempted to implement this, but the main hurdle I came across is that each of the spawner lists are different data types, so things get pretty verbose and repetitive. I think before we implement this, we need to unify the data types for the different spawners, either as a single dataclass or a set of dataclasses that inherit from a base class

[StandingPadAnimations]

Thinking about this further, a unified type system would also make easier to add suggestions as proposed in #268