Bug 29894: Send a confirmation notice

Bug 29894: Send a confirmation notice

When registering or deregistering, send a confirmation.

Test plan:
Register or deregister with patron having email address.
Verify that you got a confirmation mail.
Run t/db_dependent/Koha/Auth/TwoFactorAuth.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>