The dispatcher would kill scripts after 3 seconds, but on
heavily-loaded machines, that was sometimes too short even for simple
scripts. Bump the timeout up to 20 seconds instead (and change the
10-second quit-on-idle timer to not run when a script is running).

Also change the D-Bus call timeout in the daemon to 30 seconds, so
that it only triggers if something goes really wrong and the action
timeout fails.