feat(code): Implement Solution 2 for the RoundSync

[ancazamfir]

Closes: #XXX

From the Round sync spec:

• upon entering the round r processes broadcast the certificate EnterRoundCertificate, reset lastPrevote and lastPrecommit, and start rebroadcastTimeout
• if rebroadcastTimeout expires and the process still did not receive a round certificate for a new round a process calls REBROADCAST() and starts the rebroadcastTimeout again
• timeoutRebroadcast is approximation on how long the whole round should take so it can be something like timeoutPropose(r)+timeoutPrevote(r)+timeoutPrecommit(r)

REBROADCAST() - broadcasts the current non-nil values of EnterRoundCertificate, lastPrevote and lastPrecommit

Summary of changes as compared to parent branch anca/gossip:

• set the timeout value for rebroadcast timer to timeout_propose + timeout_prevote + timeout_precommit
• start the rebroadcast timer when entering a new round

The rest of the requirements above are already in the parent branch

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (35b4604) to head (94eb764).
Report is 1 commits behind head on anca/gossip.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@         Coverage Diff         @@
##   anca/gossip   #1032   +/-   ##
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[nenadmilosevic95]

Looks good, I did the review of this together with #997 because my understanding is that it complements it and that we want to merge it there. I left some comments but two main things are:

• do we cancel the timeout when receiving the round cert?
• do we recalculate timeoutRebroadcast to account for changes/increasing in the values of other timeouts as the round increase?