Commodore libretro docs outdated

[sonninnos]

Please update the Amiga and C64 libretro docs. A lot of things have changed since then.

https://github.com/libretro/libretro-uae/blob/master/README.md
https://github.com/libretro/vice-libretro/blob/master/README.md

Thanks!

[cmitu]

Well, thanks for making those changes ! We'll try to improve them.

[sonninnos]

I wrote proper docs in docs.libretro.com, feel free to take advantage:
https://docs.libretro.com/library/vice/
https://docs.libretro.com/library/puae/

[cmitu]

Amended the docs with #36

• Amiga (P-UAE) - https://github.com/RetroPie/RetroPie-Docs/blob/51f4fe5b294eaa9e0d07a33fed7dc643a7e892d2/docs/Amiga.md
• Libretro Vice - https://github.com/RetroPie/RetroPie-Docs/blob/51f4fe5b294eaa9e0d07a33fed7dc643a7e892d2/docs/Commodore-64-VIC-20-PET.md (NB: currently we only include the x64 core, but there's a PR to add a few more models).