CCR as a cache source

[randomthingsandstuff]

CCR is probably going to get adopted by SIDROPS. I see pros/cons to supporting it directly in stayRTR. Codebase here is a lil funky to add a new format, but its possible.

Opinions welcome.

https://datatracker.ietf.org/doc/draft-spaghetti-sidrops-rpki-ccr/