refactor: support bitmap for u8/16 and i8/16 in approx_distinct

[Weijun-H]

Which issue does this PR close?

Follow #1841
Closes #1109

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[Weijun-H]

Not sure is a proper way to measure roaring bitmap

[korowa]

Thank you @Weijun-H!

This PR, though, looks like the implementation of CountDistinct accumulator, and it doesn't seem that any approximation is performed in the code -- won't it be better to use these changes as default CountDistinct implementation for specified data types?

[alamb]

I wonder what we should do with this PR now we have

• Optimize COUNT( DISTINCT ...) for strings (up to 9x faster) #8849
• feat: native types in DistinctCountAccumulator for primitive types #8721

[korowa]

I wonder what we should do with this PR now we have

While I'm still not sure if this PR fits ApproxDistinct functionality, I suppose it might be a viable replacement for HashSets in regular CountDistinct -- so it at least worth checking / benchmarking within #1823 (paying special attention to memory consumption of bitmap-based accumulator)

[alamb]

Thanks @Weijun-H and @korowa -- I'll mark this PR as a draft now and if someone finds time to do the benchmarks we can reopen it with that in consideration

[github-actions]

Thank you for your contribution. Unfortunately, this pull request is stale because it has been open 60 days with no activity. Please remove the stale label or comment or this will be closed in 7 days.