Add tracked_sessions field to consensus service

[NotGyro]

Adds a tracked_sessions field to consensus service and a _tracked_sessions field to the client API service in consensus, as well as a ClientSessionTracking struct, to fill with tracked session information, which is a stub at present.

Motivation

Some way of keeping track of how many failed tx proposals have been sent recently needs to be available, so that bad connections can be dropped, to prevent attacks and harmful behavior from buggy clients. See: #2977

Future Work

The rest of #2977, as in:

• Populate the client session tracking structure with metadata about incoming sessions
• Keep track of how many recent failed tx proposals have been made by each client
• Drop clients which have made too many failed tx proposals in too short of a span of time.

[github-actions]

❌ Heads up, I tried building full-service using this branch and it failed.
Build logs can be found by inspecting the github action run Check that repositories submoduling us will still build after this PR / full-service or by clicking here.

[github-actions]

✅ Good job, full-service was built successfully.
Build logs can be found by inspecting the github action run Check that repositories submoduling us will still build after this PR / full-service or by clicking here.

[jcape]

There are still clippy lints that need to be fixed.

[NotGyro]

Current dependencies on/for this PR:

• master
  • PR Add tracked_sessions field to consensus service #3155 👈
    • PR Start tracking client sessions in consensus #3156
      • PR Test to ensure consensus session tracking gets populated #3172

This comment was auto-generated by Graphite.

[github-actions]

❌ Heads up, I tried building full-service using this branch and it failed.
Build logs can be found by inspecting the github action run Check that repositories submoduling us will still build after this PR / full-service or by clicking here.

[github-actions]

❌ Heads up, I tried building full-service using this branch and it failed.
Build logs can be found by inspecting the github action run Check that repositories submoduling us will still build after this PR / full-service or by clicking here.