sia agent - exit when refresh fails after configured number of attempts

[havetisyan]

let's assume we have a setup where the certs are issued for 7 days and refresh daily (default behavior).
when SIA refreshes the certs and the certificate signer is down, the refresh will fail. This will cause the sia container to exit and a new one is created. however, the cert signer might be down for a so our sia container keeps restarting. however, the existing key/cert pair is valid for at least 6 days, so there is no reason to exit.

now, we have a configurable value with default setting of 2. this means we won't be exiting if we fail to refresh our certs, instead, we'll just ignore the failure and try again tomorrow. If after 2 refresh operations, we still fail, we'll exit.

In addition, when we fail, we also check if the cert will expire before the next rotation. So even if the fail count is below the limit, if the next refresh will be too late, we'll exit as well so that the container can keep trying to fetch new certs periodically.