AS-394: Filter incorrect groups

Adding `status` filed in `scaling_groups` that will be used to filter out groups that are incorrect and are skewing our metrics. This is also the first step towards providing group status to user when the group cannot be scaled due to invalid launch configuration. 
Does this need a comma?  Not sure how to interpret the jenkins error.  Also we may possibly need a migration cql to alter the table, so we can run that on existing DB servers :)