Do not replace entries in cache when lookup has errored

This MR is a first iteration toward #281 (closed). The idea is not to replace an errored lookup in the cache once we have a correct lookup in memory. The idea is to check when an entry needs to be refreshed, if the new lookup has errored because of whatever reason (except if the ErrDomainDoesNotexist) then we simply store the same response in the refreshed entry.

It also only allows an entry to exist in the cache for a maximum of cacheExpiry duration by setting the refreshed entry created timestamp to the original entry's.

Adding acceptance tests would be possible after we finish #520 (closed)

Related to #281 (closed)