Now data for multiple tables is obtained in one call, simplifying the
use of this function. Also base table is returned as an oid, so we
now have the overview base table names with schema only when needed.
Now an error occurs before craeeteLayergroup when checking affected
tables for overviews information. This prevents the creation of the
map configuration, so the corresponding redis keys need not be deleted.
The error message changes also because now the error originates in
a different function call, QueryTablesApi.prototype.getAffectedTablesInQuery
vs getAffectedTablesAndLastUpdatedTime.
Last param is callback function, receiving err + result, no need to
keep passing two functions, the query handler and the final callback.
It should be easier to understand now as query handler was in a position
where it had to know about receiving a callback, that was exposing an
implementation detail of PgQueryRunner.
