Extend service start timeout
On a slow machine the service may take longer than 5 seconds (walltime) to start, especially during session start when multiple processes are competing for CPU time and I/O.
The original reasoning for the timeout is to limit the time to quit the process when the session is shut down, but that can be set with TimeoutStopSec.
Whether the start timeout is useful at all is questionable. It only helps if there is some deadlock during startup which would be cured by a fresh start, otherwise it is just consuming CPU time again and again.
For comparision, Gnome does not use Timeout[Start]Sec at all, but only TimeoutStopSec.