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

tests/unit/roles/svc-db-openldap/test_build_ldap_role_entries.py

@@ -42,19 +42,19 @@ class TestBuildLdapRoleEntries(unittest.TestCase):
         }
 
         self.ldap = {
-            "dn": {
-                "ou": {
-                    "users": "ou=users,dc=example,dc=org",
-                    "roles": "ou=roles,dc=example,dc=org"
+            "DN": {
+                "OU": {
+                    "USERS": "ou=users,dc=example,dc=org",
+                    "ROLES": "ou=roles,dc=example,dc=org"
                 }
             },
-            "user":{
-                "attributes": {
-                    "id": "uid"
+            "USER":{
+                "ATTRIBUTES": {
+                    "ID": "uid"
                 }
             },
-            "rbac": {
-                "flavors": ["posixGroup", "groupOfNames"]
+            "RBAC": {
+                "FLAVORS": ["posixGroup", "groupOfNames"]
             }
         }