Even trivial service occasionally get stuck, for example when
there's a problem with the journal. There's nothing more annoying
that looking at the cylon eye for a job with an infinite timeout.
Use standard 90s for jobs that do some work, and 30s for those which
should be almost instantenous.
That way ordering it with MountsRequiredFor= works properly, as this no
longer results in mount units start requests to be added to the shutdown
transaction that conflict with stop requests for the same unit.