Dynamic Collections

[SlowLogicBoy]

I like to use map filter extensively in osu! for example:
AR>=9 Stars<6

I would like to save these as collections, and when I get new maps or delete them they would update automatically (probably execute that query once I press on a collection).

Or there could be another approach to save those queries in a search dropdown list.

[peppy]

Definitely something we want in lazer.

[luaneko]

The filtering part is being done in my pr #3906