Add search bar

[srgzx]

As Apple does in their native settings app, it would be nice to have a search bar in the left column, for newer users (like me :P) who are unfamiliar with how to get to certain options, as many are kind of buried in different panes and sub-menus

[waydabber]

I'll probably add it in a future update. SwiftUI natively supports this if the app is built in a certain way, but BetterDisplay does not use that because this feature is incompatible with Monterey. In a future version when I drop Monterey support, I'll probably rework the UI to allow full-text search.

[waydabber]

#2414