[RFE] Extend support for searching with LDAP to other SAML providers

Request description:

1. Add LDAP search to the ADFS/SAML provider. Like it already exists for OKTA/SAML, and Shibboleth/SAML.
2. Spike: Look into the possibility of adding LDAP search to the Keycloak/OIDC provider.

Beware: This works with the existing structure for Auth providers. No attempt to separate searching from auth provider structures.

Note: Keycloak comes with search builtin search functionality used by our providers. (@bigkevmcd , right?). Unclear why this is not suitable to the customer.

References:

• https://jira.suse.com/browse/SURE-11095
• https://jira.suse.com/browse/SURE-10759
• PRD: https://docs.google.com/document/d/1U7qLah_sjEByR3QdKLrJgkKmsd21x8J5g3w_GJaka9c/edit?tab=t.0#heading=h.wtzwxsskg16s