feat: Preserve PeerNetwork during Epoch 3.0 transition

[jbencin]

Description

Preserve PeerNetwork struct from Neon node and pass to Nakamoto node during Epoch 3.0 transition to maintain network connections

Applicable issues

• fixes PeerNetwork state must survive from neon node to nakamoto node. #4355
• fixes bug: peernetwork bind error #4547

Additional info (benefits, drawbacks, caveats)

Checklist

• Test coverage for new or modified code paths
• Changelog is updated
• Required documentation changes (e.g., docs/rpc/openapi.yaml and rpc-endpoints.md for v2 endpoints, event-dispatcher.md for new events)
• New clarity functions have corresponding PR in clarity-benchmarking repo
• New integration test(s) added to bitcoin-tests.yml

[jbencin]

@kantai @jcnelson I'm having trouble thinking of a good way to test this. I'm not sure what I would check in PeerNetwork to prove it wasn't re-created, and I can't really access it from outside StacksNode::spawn() anyways. Right now I'm thinking I could use TestPeer, or just open a raw TCP socket, and check if it gets disconnected. Any better ideas?

[jbencin]

Also the following tests are failing, but also fail on develop as of e79719d:

• tests::nakamoto_integrations::follower_bootup
• tests::signer::stackerdb_mine_2_nakamoto_reward_cycles

[obycode]

LGTM!