drill

b249baf0 - DRILL-7985: Support Mongo aggregate, union, project, limit, sort pushdowns (#2289)

DRILL-7985: Support Mongo aggregate, union, project, limit, sort pushdowns (#2289) * DRILL-7985: Support Mongo aggregate, union, project, limit, sort pushdowns * Fix ser/de, make batchSize configurable and minor cleanup * Add docs for Mongo storage plugin credentials * Update mongo driver * Fix CASE with multiple branches * Fix alert