docs: add guidance for setting GPU for encoding in ALVR

[dvtfl]

Relevant issue: #2325
Relevant Discord thread

[The-personified-devil]

There's multiple other options that should work, and this one combines quite poorly with them, so I'd only like to add this if the other fixes don't work because otherwise I think it'd be a bit confusing having multiple solutions to the same problem. Even if so it needs to be reworded to show that both are potential solutions to the same problem and should both be tried. Plus a very simple guide on how to find the right file for your distro might be nice

[32bitx64bit]

Seems more confusing than helpful in my eyes.

[Meister1593]

I think this should be closed if no changes are being done over this and other ppl disagreeing too. What do you think @The-personified-devil ?

[dvtfl]

Apologies for the late response, i was being ill.

There's multiple other options that should work

Could you please name them?

[The-personified-devil]

Could you please name them?

They're listed on the wiki page already. You could perhaps add this as a sort of addendum along the lines of "if that doesn't work also add this option". But relying on it alone isn't a good idea and the other options should already work if nvidia didn't break/change anything.