Refactor LDAP variable schema to use top-level constant LDAP and nested ALL-CAPS keys.

- Converted group_vars/all/13_ldap.yml from lower-case to ALL-CAPS nested keys.
- Updated all roles, tasks, templates, and filter_plugins to reference LDAP.* instead of ldap.*.
- Fixed Keycloak JSON templates to properly quote Jinja variables.
- Adjusted svc-db-openldap filter plugins and unit tests to handle new LDAP structure.
- Updated integration test to only check uniqueness of TOP-LEVEL ALL-CAPS constants, ignoring nested keys.

See: https://chatgpt.com/share/68b01017-efe0-800f-a508-7d7e2f1c8c8d

roles/svc-db-openldap/tasks/01_credentials.yml

@@ -28,7 +28,7 @@
 - name: "Generate hash for Database Admin password"
   shell: |
     docker exec {{ openldap_name }} \
-      slappasswd -s "{{ ldap.bind_credential }}"
+      slappasswd -s "{{ LDAP.BIND_CREDENTIAL }}"
   register: database_admin_pw_hash
 
 - name: "Reset Database Admin password in LDAP (olcRootPW)"