Ensure the url_alias table is created when the module is installed

This is a workaround for until #2704821: url_alias table should be created by system install is committed to core, to avoid issue with the url_alias table not being available to query until an alias has actually been created. Pathauto *always* tries to query before alias creation, so we need to ensure this table exists. This was introduced in #2664466: url_alias table is only used by a core service but it depends on system install.