[FEA] Story - Supporting Approximate Count Distinct

[ttnghia]

This issue tracks the dependencies for supporting approximate count distinct using HyperLogLog algorithm.

• Design doc (WIP): https://docs.google.com/document/d/1ezAXhH7GejuaNDvIyqMBYfmsSypcDWinl2_tmLJd-O4

[jrhemstad]

Given there was already sizable discussion in #10652, can we just use that issue? Or is there a different intent with this one?

[ttnghia]

That issue has been diluted.
Here I'm going to add checked list item for the necessary PRs/features we are going to add so people can keep track, like this: #10186.

[revans2]

This is still wanted