PeerManager: prioritize peers to disconnect

[twoeths]

Is your feature request related to a problem? Please describe.

We need a strategy to prioritize peers to disconnect. At least we need to select peers with least long-lived subnets to disconnect, refer to https://github.com/sigp/lighthouse/blob/1829250ee4df6c4e69687ccdcc69ab79d968e986/beacon_node/lighthouse_network/src/peer_manager/mod.rs#L883

Describe the solution you'd like

• Work on this TODO:

  lodestar/packages/lodestar/src/network/peers/utils/prioritizePeers.ts

  Line 97 in bdeef8d

  // TODO: Priotize peers for disconection better, don't just filter by duty but

• New metrics to show long-lived subnets of our peers and track it over time to make sure that's an improvement

• Any changes to the network/peer manager are critical so need to test the work carefully

[philknows]

Good follow up step to gossipsub resolution.

[twoeths]

close via #3955