Bug 20074: Database revision to convert hidden to -5

Bug 20074: Database revision to convert hidden to -5

The hidden value is used as a boolean in authority frameworks (in contrast
with biblio framework).
It is consistent to apply the same value (-5) to all non-zero values.

Test plan:
Check if you a have 0, 1 and 8 value in hidden somewhere.
Run the dbrev.
Verify that 1 and 8 are converted to -5.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>