computeBootstrapDelay should use timestamps to estimate the delay instead of epochs

[Kubuxu]

If the node starts with EC state behind, it can wait for the bootstrap even though it is unnecessary.
Instead, we should use now() vs head.Timestamp() + (bootstrap - head.Epoch)* mani.EC.Period.

go-f3/f3.go

Lines 136 to 160 in 163115a

	func (m *F3) computeBootstrapDelay() (time.Duration, error) {
	manifest := m.manifest.Load()
	if manifest == nil || manifest.Pause {
	return 0, nil
	}
	ts, err := m.ec.GetHead(m.runningCtx)
	if err != nil {
	err := fmt.Errorf("failed to get the EC chain head: %w", err)
	return 0, err
	}
	currentEpoch := ts.Epoch()
	if currentEpoch >= manifest.BootstrapEpoch {
	return 0, nil
	}
	epochDelay := manifest.BootstrapEpoch - currentEpoch
	start := ts.Timestamp().Add(time.Duration(epochDelay) * manifest.EC.Period)
	delay := m.clock.Until(start)
	// Add additional delay to skip over null epochs. That way we wait the full 900 epochs.
	if delay <= 0 {
	delay = manifest.EC.Period + delay%manifest.EC.Period
	}
	return delay, nil
	}

[masih]

I was wondering if EC state is behind, should it start at all. But then at the time of finalization we'd wait for chain sync anwyay. What about getting proposal when EC is behind?

[Kubuxu]

The point is to start F3 so it can start fetching the cert chain, so we can easily sync the canonical chain.