Followups from `UsageDataQueries` API

Discussion on !57016 (comment 537720603) should be addressed.

A documentation MR - !57564 (merged)
An MR to bypass unnecessary min/max queries in CE_MEMOIZED_VALUES. - !58006 (merged)
Reducing the endpoint execution time to a few seconds with further optimizations if necessary. - !59365 (merged)

Edited Apr 23, 2021 by Rajendra Kadam