Remove non-functional Joomla LDAP integration

- Disabled LDAP feature flag (set to false by default, with comment)
- Removed ldapautocreate plugin (PHP + XML)
- Deleted LDAP helper tasks (01_ldap_files.yml, 05_ldap.yml, 07_diagnose.yml)
- Deleted LDAP CLI helper scripts (cli.php, diagnose.php, plugins.php, auth-trace.php)
- Removed LDAP configuration variables from vars/main.yml
- Removed LDAP environment variables from env.j2
- Removed LDAP-specific mounts from docker-compose.yml.j2
- Dropped php-ldap installation from Dockerfile
- Renamed task files for consistent numbering (02->01_install, 03->02_debug, 04->03_patch, 06->04_assert)

Reason: LDAP integration was removed because it was not functional.

Conversation: https://chatgpt.com/share/68b09373-7aa8-800f-8f2c-11e27123bad1

roles/web-app-joomla/config/main.yml

@@ -5,7 +5,8 @@ features:
   desktop:            true
   central_database:   true
   logout:             true
-  ldap:               true
+  ldap:               false # There is no working free open source LDAP solution 2025-08-28
+  oidc:               false # There is no working free open source OIDC solution 2025-08-28
 server:
   domains:
     canonical: