Bug 29137: Add new syspref to disable AV creation within the cataloguing module

Bug 29137: Add new syspref to disable AV creation within the cataloguing module

"I don't like this patch at all!"
"We will see a cataloger revolt if we do not find a way to make this
optional for catalogers."

I imagined a hord of catalogers running behind me and I got scared.

This patch will allow to turn the new feature added by bug 25728 off.

Test plan:
Confirm that the new CreateAVFromCataloguing will permit to turn the
feature off.

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>