fix(roles/mariadb_server): inherit server default charset/collation for new databases

Author: NavidSassan

CHANGELOG.md

@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* **role:mariadb_server**: Databases created via `mariadb_server__databases` without an explicit `collation` or `encoding` now inherit the server default character set and collation (utf8mb4) instead of being pinned to the legacy `utf8` / `utf8_general_ci` (utf8mb3, no full Unicode). Existing databases are unaffected; set `collation` / `encoding` per database to override.
 * **role:collabora**: Support Collabora Online CODE 25.04.10. The role ships one `coolwsd.xml` template per CODE release and had none for this version, so it aborted the deploy on hosts that had updated to it.
 * **role:clamav**: Send notification mails through `sendmail` (provided by postfix) instead of the `mail` command (mailx). One invocation works across distributions, and delivery no longer depends on mailx being installed.
 * **role:icingadb, role:icingaweb2, role:icingaweb2_module_reporting, role:icingaweb2_module_x509, role:mariadb_server**: Move the MariaDB tasks from the deprecated `community.mysql` collection to its replacement `ansible.mysql`. Behaviour is unchanged, but the deprecation warnings printed on every run are gone and the roles keep working once `community.mysql` is removed upstream.

roles/mariadb_server/README.md

@@ -227,11 +227,13 @@ mariadb_server__dump_user:
 
         * Optional. DB collation.
         * Type: String.
+        * Default: empty; the database inherits the server default (`mariadb_server__cnf_collation_server__combined_var`).
 
     * `encoding`:
 
-        * Optional. DB encoding.
+        * Optional. DB encoding (character set).
         * Type: String.
+        * Default: empty; the database inherits the server default (`mariadb_server__cnf_character_set_server__combined_var`).
 
     * `state`:
 

roles/mariadb_server/tasks/main.yml

@@ -717,8 +717,8 @@
       login_password: '{{ mariadb_server__admin_user["password"] }}'
       login_unix_socket: '{{ mariadb_server__cnf_socket__combined_var }}'
       name: '{{ item["name"] }}'
-      collation: '{{ item["collation"] | default("utf8_general_ci") }}'
-      encoding: '{{ item["encoding"] | default("utf8") }}'
+      collation: '{{ item["collation"] | default(omit) }}'
+      encoding: '{{ item["encoding"] | default(omit) }}'
       state: '{{ item["state"] | default("present") }}'
     loop: '{{ mariadb_server__databases__combined_var }}'
     loop_control: