Save file location based on hash/title id

[whocares0101]

For example I have the same rom but with different filenames e.g. "Some Game.bin" and "Some Game (v1).bin"
Now RetroArch will create a save file for each file instead of sharing it.
I'd like to be able to have the save file location based on the hash of the rom, the title id (e.g. SLUS-01324), or the RetroAchievements hash maybe.
This way if I have the same rom with different filenames or if the rom got renamed the correct save file will be used.

Create a sub-directory per hash and store all relevant save data there.

saves/<hash>/sram.srm

saves/<hash>/slot1.mcr
saves/<hash>/slot2.mcr

Save states should also use a sub-directory based on the core library name.

states/mednafen_psx_hw_libretro/<hash>/0.state
states/mednafen_psx_hw_libretro/<hash>/autosave.state

Existing data should be imported if no save is in the new location yet.