Added the status trend report and API

- Report supports filtering by date and any one of: sku,
  entitlement name or the management_enabled entitlement
  attribute.
- The database query and general data gathering is performed
  by the ComplianceSnapshotCurator.
- The request is processed by the StatusTrendReport class.
Moving all but  *mapper.readValue(...)* out of the try/catch would tidy this up a little. It is the only thing in there that throws that exception.