Bug 23538: Email library when new patron self-registers

Bug 23538: Email library when new patron self-registers

Test plan:
1. Apply all patches
2. Update database
3. Restart services
4. Set email addresses in:
- KohaAdminEmailAddress syspref
- EmailAddressForPatronRegistrations syspref
- Email address in the library branch
5. Enable PatronSelfRegistration syspref
6. Test the following use cases:

- EmailPatronRegistrations syspref = 'none'.
Submit OPAC registration.
= OUTCOME: Confirm no OPAC_REG notice in message_queue table

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>