Add SSO hostname/fqdn to certs generated for SAML provider hosts (Bug #56483)

[RustyDust]

Since these certificates are used in the various other services as well like samba and ldap this allows for defining external LDAP auth clients using the SSO fqdn with certificate checking enabled.

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Link to the issue in Bugzilla

https://forge.univention.org/bugzilla/show_bug.cgi?id=56483)

Description of the changes

Adds the SSO hostname/fqdn to certificates created for hosts defined as SAML providers

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