Roundcubemail: Add user-domain-changed to auto discover ldap settings

[stephdl]

Roundcubemail does not auto discover the LDAP settings automatically, it is done when we press the button save in the settings page. The LDAP is used for the contact address book

Proposed solution

We needs to register to the event user-domain-changed and to add a script to auto discover the ldap settings on a service restart

Alternative solutions

click on the button configure when the account provider has changed

[stephdl]

Version to test ghcr.io/nethserver/roundcubemail:2.0.5-dev.1

The simplest way could be to migrate from NS7 to NS8 with the version nethserver-ns8-migration
write to the /usr/share/nethesis/nethserver-ns8-migration/apps/nethserver-roundcubemail/bind.env the version above and migrate the mail stack to a NS8

• install NS7 with an openldap account provider, mail and sogo
• install the testing version of nethserver-ns8-migration
• modify the bind.env to get the version of roundcubemail
• migrate the stack
• at the end of the account provider migration, the event user-domain-changed is triggered
• once the stack is migrated, you can login to roundcubemail with a user (do not reconfigure something)
• go to the contact address book, the LDAP one is available, you can see the user of the LDAP, prefilled user are available when you send an email