* feat: flags for pushing down new aggregates
* refactor: grouped aggregate rewrite rules
The storage operation ReadGroup aggregates per series on the storage
side. The planner will rewrite grouped aggregate queries to call
ReadGroup, which will perform a partial aggregation, followed by
another operation that will perform the rest of the aggregation on
the compute side.
* feat: storage capabilities for grouped aggregates
* fix: changes from review
* feat: group read operation name should include aggregate
Faith Chikwekwe
jlapacik
Yiqun (Ethan) Zhang