Tune peering part 1

[Menduist]

Extracted from #3346

Includes:

• Request metadata_v2 (altair) by default instead of the v1
• Change the metadata pinger to a 3 failure-then-kick, instead of being time based
• Update kicker scorer to take into account topics which we're not subscribed to, to be sure that we will be able to publish correctly
• Add some metrics to give "fanout" health (in the same spirit of mesh health)

[arnetheduck]

looking forward to seeing these fanout metrics and how they stack up against the mesh, should prove valuable

[github-actions]

Unit Test Results

     12 files     806 suites   34m 13s ⏱️
1 652 tests 1 604 ✔️   48 💤 0 ❌
9 665 runs  9 561 ✔️ 104 💤 0 ❌

Results for commit 2b5354a.

♻️ This comment has been updated with latest results.