Add metrics for initial peer network protocol versions

[teor2345]

Motivation

As part of ticket #2797, we want to check the network protocol versions of the peers supplied by the Zcash DNS seeders.

Designs

Zebra already has this information, we just need to add it to the logs and metrics.

Solution

Seed Peer DNS Resolution:

• log the initial peers resolved from each seed
• add metrics for initial peer resolution, including the seed and remote peer IP
• add a grafana dashboard for seed peer resolution
• add a per-seed filter to the peer dashboard

Network Protocol Versions

• add tracing and metrics for peer network protocol versions
• add network protocol versions to peers dashboard
• show peer network protocol versions for each seeder in the peer dashboard

Review

Anyone can review this PR, but I think @conradoplg or @upbqdn have set up a Grafana instance already?

Merging this PR isn't urgent.

Reviewer Checklist

• Code records metrics and logs correctly
• Dashboards work

Follow Up Work

• Create a DNS seeder health check utility #2137
• Re-deploy the foundation's DNS seeders for NU5 testnet #2797
• Add dev zones for testing DNS seeders #2812

[teor2345]

This is what the mainnet dashboards look like (for seed peers and all peers):

[teor2345]

This is what the testnet dashboards look like:

[upbqdn]

This is what the mainnet dashboards look like for me for the first four minutes of running Zebra:

[upbqdn]

Here are the first few minutes of running on Testnet:

[upbqdn]

Adding dev.testnet and dev.mainnet also seems to be a good idea.