Existing deployments using MySQL or Percona Server with `services.mysql`
do not restrict authentication to the root@localhost user allowing any
user on the system to log in without a password.
With this changes:
* new deployments will use the `auth_socket` authentication by default
to only allow the local root user to log in as the MySQL root user
* existing deployments with a stateVersion > 26.05 will also be moved to
the `auth_socket` authentication
* existing deployments with a stateVersion <= 26.05 have a warning
logged when the local authentication seems to be open
Users can disable this behavior by setting `services.mysql.secureSuperUserByDefault`
to `false`.
Thomas Gerbet
1d6947077e