control: Add a key to GETINFO to fetch the circuit onion handshake rephist values
Basically something that would export the rephist value of the onion handshakes:
onion_handshakes_assigned
onion_handshakes_requested
The heartbeat uses rep_hist_log_circuit_handshake_stats()
to log the ntor and tap stats. I want those from the GETINFO command in order to be able to graph and keep stats over time of those values.