Derives from the decision in #2184 to make the SynchronyParams.MessageDelay PBTS parameter adaptive.

The defined mechanism is:

1. Precision parameter remains unchanged over consensus rounds
2. MessageDelay parameter increases over consensus rounds, with the following logic:

MessageDelay(round) = MessageDelay * (1.1)^round

Definition of Done

• Implement logic for MessageDelay to increase over rounds and associated testing
  • feat(pbts): Make synchrony params adaptive #2431
• Adopt this this logic on the consensus implementation
  • feat(pbts): Make synchrony params adaptive #2431
• Test that a Proposal with timestamps far in the past is eventually decided in a height of consensus, provided that multiple rounds are executed
  • test: untimely proposals must be decided after multiple rounds #2447
  • Merge into feat(pbts): Make synchrony params adaptive #2431 branch
• Address comments on feat(pbts): Make synchrony params adaptive #2431
  • feat(types): improve Proposal and SynchronyParams validation tests #2489
  • feat(types): refactor types.AdaptiveSynchronyParams method #2490