Add R as an interpreter

[hiphof]

Add R as an interpreter

This should be implemented in a similar way as how Perl #1229 was implemented.

In scope

• Add a R test section, like is done with Perl feat: add a perl test section #1230. For how a R-specific test section could look like, see #790#issuecomment-2509140463.
• Add some R docs (see Perl example docs: add some perl docs #1234 )

[wolfv]

Yes, this would be quite cool! Let me know if you have any questions :)