[bifrost] Keygen Retries and ChurnRetryInterval Mimir

Resolves #1585 (closed) - will separate out the seed refresh component noted on a comment there into a separate issue after this since it will also require more changes in go-tss. This is just a draft and has seen no testing, just pushing for now in case someone wants to carry the torch, otherwise will continue with this testing next week.

This has been tested with paths noted in comment below. Also this was extended to read a mimir for the ChurnRetryInterval.

bifrost/signer/sign.go

@@ -376,8 +376,8 @@ func (s *Signer) scheduleRetry(keygenBlock ttypes.KeygenBlock) bool {
 	retryIntervalDuration := time.Duration(keygenRetryInterval) * constants.ThorchainBlockTime
 	if retryIntervalDuration <= s.cfg.KeygenTimeout*3/2 {
 		s.logger.Error().
-			Dur("retryInterval", retryIntervalDuration).
-			Dur("keygenTimeout", s.cfg.KeygenTimeout).
+			Stringer("retryInterval", retryIntervalDuration).
+			Stringer("keygenTimeout", s.cfg.KeygenTimeout).
 			Msg("retry interval too short")
 		return false
 	}