min() and max() should support booleans

[LEW21]

min() and max() should be supported for booleans.

Current behavior: ERR: unsupported max iterator type: *influxql.booleanInterruptIterator

Desired behavior: handle true as 1 and false as 0 - return max(field) == true iff at least one row has the field set to true.

Use case: We're storing some boolean data near other, numeric stats, and want to downsample them with Continuous Queries. We only need to know if they were true at least once in the given time.

[LEW21]

Thanks!