Linux Desktop Support #238

Hello! This is sort of an extension to #210 and #235 but more focusing on Linux support in general without any dependence on another software (RetroDECK/EmuDeck/Batocera/etc).

I primarily use a mix of a manually set up ES-DE install (https://es-de.org/), Steam ROM Manager, and the emulators themselves to launch my ROMs on a Linux desktop and handhelds (Steam Deck primarily). On initial launch, ES-DE prompts to create a list of ROM folders in a directory of your choice which I use for my own ROM management.

It would be great if Grout could maybe work independently from any front-end or software suite and on initial launch prompt the user to select a directory for ROMs and BIOS and create the folders needed. Alternatively, it could use ES-DE's pre-existing folders.

Thanks for your work on this software!