Graph and values are identical for TOTAL and N/A

STR:

Open QAN
Change Group by to Database, Schema or User Name

Actual result:

The graph and values are identical for TOTAL and N/A

Expected result:

Values should be different and TOTAL should show total of all rows

Proposed solution:

 - pass argument isTotal to SelectSparklines function;

 - improve query template to check if code tries to query the total or empty value of dimension:

https://github.com/percona/qan-api2/blob/master/models/reporter.go#L235