Bug 33940: Move C4::Members cardnumber sub to Koha::Policy::Patrons::Cardnumber

Bug 33940: Move C4::Members cardnumber sub to Koha::Policy::Patrons::Cardnumber

Test plan:
The idea here is to confirm this patch does not introduce regression.
For that you will play with the CardnumberLength syspref and create a
new user, modify an existing one, and check that the UI does not let you
modify an invalid cardnumber.
The onboarding process and the patron import tool will also have to be tested

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Bug 33940: Fix selfreg

please squash with first patch

Bug 33940: Fix messages we sent to templates

please squash with the first patch

Bug 33940: Fix what we send to memberentry

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>