[Feature request] Automatic savestate option

[kat-sudo-n]

I was wandering if it could be possible to add an option to tell the emulator to make an automatic savestate every half an hour or so. By default it could be disabled but enabled by the user if they want. This is to prevent potential crashes with games having trouble with savestates like I saw here #784.

[NPO-197]

This is a good use case for Lua scripts from PR #1671 . It'd be quite easy to write a simple lua script that automatically makes a savestate every half hour or so, and would be very easy for users to then customize the script further as needed. So for example stuff like the location and names of auto savestate files, number of backups to keep, how often and under what conditions to make a save state, could all be specified in the lua script file.