DRILL-1950: Parquet rowgroup level filter pushdown in query planning time.
Implement Parquet rowgroup level filter pushdown. The filter pushdown is performed in
in Drill physical planning phase.
Only a local filter, which refers to columns in a single table, is qualified for filter pushdown.
A filter may be qualified if it is a simple comparison filter, or a compound "and/or" filter consists of
simple comparison filter. Data types allowed in comparison filter are int, bigint, float, double, date,
timestamp, time. Comparison operators are =, !=, <, <=, >, >=. Operands have to be a column of the above
data types, or an explicit cast or implicit cast function, or a constant expressions.
This closes #637
