Make cheat import UI clearer

[hrydgard]

If you press "Import from Cheats.db" and no file is there, nothing happens.

It should probably tell the user where to put the file. Also, could be interesting to store cheat.db files on the homebrew store for easy automatic download - and maybe just automatically import cheats if a cheats.db file exists, when opening the cheats dialog for a game?

Also, the "Enable cheats" option should possibly be removed?

[unknownbrackets]

By the way, some years ago when I changed the parsing of cwcheat files to build a "bytecode", I made it able to parse a cheat file with multiple games in it. I think it was necessary to "import from" such a file before, because the code would run ALL cheats, even unrelated to this game (there's some _G ULES-12345 headers.)

Maybe we could even just get rid of the "import" step? It would be like the PSP then, I think?

I think the option to enable/disable cheats were discussed in #8171. I will say it is common that it causes crashes/problems and many emulators have an easy on/off switch for cheats. If we remove it, we may end up with people wanting "cheat profiles" so they have a way to temporarily turn on those hacky cheats they use that only work when they are i.e. in a race.

-[Unknown]