[FEATURE] separate LDAP search function for AD and freeIPA

[flyinghermit]

Describe the feature: Currently, we've used a generic LDAP search function that will only(some works with FreeIPA as well) work in Active Directory. Make different search function for freeIPA and AD to handle edge cases

Describe why this feature is needed: Better support for both AD and FreeIPA IDP

Scope of the feature:

• [ ] TRASA codebase
• [ ] dashboard
• [x] server
• [ ] mobile app
• [ ] browser extension
• [ ] device agent
• [ ] website/docs