Add migration to create new settings for admin contacts validation:
- admin_contacts_required_for_org: boolean setting to require admin contacts for organizations
- admin_contacts_required_for_minors: boolean setting to require admin contacts for minors
- admin_contacts_allowed_ident_type: array setting to specify allowed identification types for admin contacts
The migration safely handles existing settings by checking for their presence before creation.
Default values are set to maintain backwards compatibility while enforcing new validation rules.
