Use stale views in the TaskArchiver

In agents with high load, the JobDump and FWJRDump design views
are always updating and therefore stale views must be used there.
The TaskArchiver data collection happens late enough that a stale
view shouldn't cause problems with missing data.

Unfortunately, CouchDB doesn't accept stale on lists. For those
we have to catch the timeout exceptions and move on.
Merge pull request #4675 from dballesteros7/task-archiver-stale

Use stale views in the TaskArchiver