DirPort can't fetch router status entries by fingerprint
Tor's DirPort provides server and extrainfo descriptors by fingerprint, this is great!
However, it lacks a counterpart for router status entries. Callers can retrieve the whole consensus...
... but not individual relays.
Tor doesn't need this, but it would be really handy for callers of stem's remote descriptor module. I just noticed this was missing because I wanted to improve the control interpreter to not rely on local descriptors for its /info lookups (since that's frequently stale, causing confusion) but realized I couldn't without pulling the full consensus. :(