Stream chunks from ingesters to querier when running the blocks storage

[pracucci]

When running a query in a Cortex cluster running the chunks storage, the querier fetches (encoded) chunks from ingesters and these chunks are decoded in the querier itself.

On the contrary, when running the blocks storage, the chunks are decoded in the ingester and the querier fetches (decoded) SeriesSet from ingesters. This puts extra pressure on the ingesters, based on the query QPS and the number of series touched by each query.

We want to stream chunks from ingesters to querier in the blocks storage too.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[pracucci]

Still valid. Now TSDB supports chunks-based querier/iterator, so we can build it.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[pracucci]

Still valid.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[jtlisi]

still valid

[jtlisi]

Closed by #3889