Load other cores from LibRetro (e.g. SameBoy, etc)

Is your feature request related to a problem? Please describe.
I don't know about Lemuroid modularity but sometimes I want or need to use a core like bsnes or SameBoy.

Describe the solution you'd like
If that modularity is possible, add an option to load external cores downloaded from LibRetro Buildbot under advanced settings.

Describe alternatives you've considered
Just use RetroArch, but is pretty hard to setup and isn't easy to use.

Additional context
This should help with accuracy issues on actual supported systems, and I'm not talking about adding more system, just core alternatives.