IBX-8855: Ensure DDEV's MySQL character set & collation (#2481)

---------

Co-authored-by: Marek Nocoń <mnocon@users.noreply.github.com>

docs/getting_started/install_with_ddev.md

@@ -71,6 +71,16 @@ Now, configure the database connection for your [[= product_name =]] project. De
     ddev config --web-environment-add DATABASE_URL=mysql://db:db@db:3306/db
     ```
 
+    To ensure consistent character set when performing operations both in Symfony context and with the `ddev mysql` client add the following database server configuration.
+
+    Create the file `.ddev/mysql/utf8mb4.cnf` with the following content:
+
+    ```cfg
+    [mysqld]
+    character-set-server = utf8mb4
+    collation-server = utf8mb4_unicode_520_ci
+    ```
+
 === "PostgreSQL"
 
     ```bash