##### SUMMARY
mysql_db module should be able to create/drop multiple databases

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
lib/ansible/modules/database/mysql/mysql_db.py

##### ADDITIONAL INFORMATION
Why and what it would solve:
Avoids repetitive tasks to create/delete more than one databases (similar to https://github.com/ansible/ansible/issues/56059)

<!--- Paste example playbooks or commands between quotes below -->

- Create (Multiple databases)
```yaml
  tasks:
  - name: Create multiple databases (provided in comma separated form)
    mysql_db:
      name: bobdata, bobthebuilder
      state: present
  - name: Create multiple databases (provided in list form)
    mysql_db:
      name:
        - bobdata
        - bobthebuilder
      state: present
```

- Delete/Drop (Multiple databases)
```yaml
  - name: Delete/drop multiple databases (provided in comma separated form)
    mysql_db:
      name: bobdata, bobthebuilder
      state: absent
  - name: Delete/drop multiple databases (provided in list form)
    mysql_db:
      name:
        - bobdata
        - bobthebuilder
      state: absent
```

Credits for the idea to @Andersson007 from comment https://github.com/ansible/ansible/pull/56721#issuecomment-505128646
module.exit_json(changed=True, db=db_name)
            rc, stdout, stderr = db_dump(module, login_host, login_user,
                                         login_password, db, target, all_databases,
                                         login_port, config_file, socket, ssl_cert, ssl_key,
                                         ssl_ca, single_transaction, quick, ignore_tables)
            if rc != 0:
                module.fail_json(msg="%s" % stderr)
            else:
                module.exit_json(changed=True, db=db_name, msg=stdout)
        elif state == "import":
            if module.check_mode:
                module.exit_json(changed=True, db=db_name)
            rc, stdout, stderr = db_import(module, login_host, login_user,
                                           login_password, db, target,
                                           all_databases,
                                           login_port, config_file,
                                           socket, ssl_cert, ssl_key, ssl_ca)
            if rc != 0:
                module.fail_json(msg="%s" % stderr)
            else:
                module.exit_json(changed=True, db=db_name, msg=stdout)
        elif state == "present":
            module.exit_json(changed=False, db=db_name)
    else:
        if state == "present":
            if module.check_mode:
                changed = True
            else:
                try:
                    changed = db_create(cursor, db, encoding, collation)