Bug 16330: Remove validation code from Koha::Patron

Bug 16330: Remove validation code from Koha::Patron

This patch removes previously added validation code from Koha::Patron
as we will rely on the DB structure and relationships to catch the same
problems. This is implemented on bug 19828.

This patch also adapts the API controller class to expect this behaviour
change from Koha::Patron. The expected exceptions are adjusted, and some
minor changes take place. The API tests are adjusted as well.

To test:
- Run:
  $ kshell
 k$ prove t/db_dependent/Koha/Patrons.t
 k$ prove t/db_dependent/api/v1/patrons.t
=> SUCCESS: Tests should still pass

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>