Allow Changing Saves and States Directory

[JukeboxZulu]

On newer Android versions, the Android/data folder is no longer writeable without root and is not readable by most apps. This means that saves and savestates cannot be easily imported, exported, or synced.

Allowing users to set their own directory for saves would make it much easier to import saves from other emulators and to sync with different platforms (e.g. Retroarch on desktop).

[TRIPSLORD]

Right now this is the only thing stopping me from using lemuroid