WTF-PAD: Log padding counters into the heartbeat

We should tie the padding counters in circuitpadding to the heartbeat so that we can see (at least on the relays) how much padding we are sending/receiving.

changed milestone to %Tor: unspecified

added 041-proposed component::core tor/tor milestone::Tor: unspecified padding priority::low severity::normal sponsor::2 status::new tor-cell tor-relay type::defect wtf-pad labels

Move all WTF-PAD tickets that do not have a sponsor into sponsor2.

Trac:
Sponsor: N/A to Sponsor2

This is nice to have as a convenience, but this info is already in the extrainfo descriptors. A higher priority is making sure that extrainfo material is correct/useful, I think.

Trac:
Parent: #28632 (moved) to N/A

Trac:
Milestone: Tor: 0.4.1.x-final to Tor: unspecified
Priority: Medium to Low

If any researcher would find this useful, let me know.

moved to tpo/core/tor#29840 (closed)