[Consensus2] - Decouple quorum proposal task

[jparr721]

Closes #3171

This PR:

Right now the quorum proposal task relies on calling the existing consensus functions, but isolates the call site so that way it can exist in an idempotent manner. This has created some issues due to the need to keep backwards compatibility with the consensus task. Instead, we will author our own new logic and only reuse functions that have limited scope. Specifically:

• Makes a new Quorum Proposal Task module which will hold all relevant logic for that task
• Fully removes all references to the old consensus task unless the functionality will live on in the new tasks
• Fully tests and evaluate all new code in the unit testing suite to ensure that all expected behaviors are understood.

This PR does not:

• Handle upgrades.
• Handle the situation where the parent isn't found in the propose routine.

Key places to review:

• Please look at all instances of ValidatedStateUpdated, as this method is a gating requirement to be able to propose. Does it make sense to gate on this method? This updates validated_state_map, which we use when we propose.
• Please look at my re-implementation of the leaf traversal
• Please look at my unit tests, and answer the following questions to yourself. If ANY of it is unclear, let me know ASAP.
  • Is QuorumProposalValidated referencing the right proposal and leaf?
  • Is the test_view_1 test evaluating the right genesis views?
  • Do the new events make sense?
  • Are timeouts and view sync handled properly?
• Do these dependencies make sense?
  • Please see the design document in notion for additional explanation.
• Does blocking on the consensus high qc update make sense?
  • Please see the design document in notion for additional explanation.

Also PLEASE look at the design doc in notion! It features a deep-dive of all the changes as well as their motivation.

[shenkeyao]

Looks good, just a comment about reordering code.

[shenkeyao]

LGTM