Bug 17187: Lower the timeout preference from 139 days to 1 day

Bug 17187: Lower the timeout preference from 139 days to 1 day

Default timeout is now 12000000 seconds == almost 139 days !
Surely, your session will be shorter. But we should lower this
value.
Balancing usability and security, I propose 1d (1 day) now.
Current pref value will be affected only if it is NULL or equal
to the old default.

Test plan:
Check your current value. Optionally change to NULL or 12000000.
Run the dbrev and see what happens.
Beware of cached values while testing or flush the cache.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>