Implement Rendezvous Circuit Close Statistics

[teor2345]

We plan to collect everything when the circuit closes.
This avoids having to write byte transfer and establish rendezvous events.

Tor trac #13792:

• Established time: Time from the creation of the rdv point up to finishing handling the RENDEZVOUS_ESTABLISHED cell.
• Establish rdv to RENDEZVOUS2 cell: Time from the ESTABLISH_RENDEZVOUS cell to the RENDEZVOUS2 end of processing cell.
• Ready time: Time from the creation of the rdv point up to receiving the RENDEZVOUS2 cell which indicates that data is ready for transmission.

Tor trac #13194:

• Track time between ESTABLISH_RENDEZVOUS and RENDEZVOUS1 cell

Tor trac #13509:

• How many RPs do we try before suceeding at connecting?
• How often do we use preemptive circuits?
• How often do we cannibalize circuits?

Tor trac #13466:

• TAP vs ntor

Tor trac #18082:

• Tor2web (client connecting directly to rend - large bias by Tor2webRendezvousPoints)
• Single Onion Services (service connecting directly to rend - small bias by Tor2webRendezvousPoints?)

Our #309:

• Ratio of HSDir bytes to bytes of traffic (HSDir and Rend)
• the ratio of introductions to rendezvous overall (intro and rend)
• the ratio of rendezvous overhead to bytes of traffic

Our #10:

• successful and failed rendezvous
• circuit lifetime
• data quantity

Our #310:

• the time between rend establishment and the service connecting