[Switch port] add configurable hotkeys

[eadmaster]

Add a secondary settings menu to customize the emulator hotkeys, like the Qt port has.

e.g.:
ZL=quicksave
ZR=quickload
RS-up=open menu
RS-right=fastforward
RS-left=rewind

[endrift]

There are already configurable hotkeys, but not all of those options are available. Rewind is not present in the Switch version at all at the moment.

[eadmaster]

i'm running the latest stable v0.10.5 currently... where are they documented/defined?

(i've only seen hotkeys in the Qt port )

[eadmaster]

nevermind, i've found them in the "Remap controls" submenu , and i was able to add the hotkeys i wanted:

eadmaster@ac636ae