feat(tdigest): add tdigest algorithm and storage encoding implementations

[LindaSummer]

Issue

• Tracking Issues: support t-digest data structure and commands #2558

Proposal

• T-Digest Design Proposal #2542

Proposed Changes

• add tdigest core algorithm support.
• add encoding and decoding method as designed.
• add core implementations for create, add and quantile.
• add basic unit tests for create, add and quantile.

TODO List

• add more unit tests for corner cases and benchmark.
• find a more stable way to evaluate the error of quantile.
• refactor the DummyCentroids to an iteration way for efficiency.
• integrate the core implementations to commands and add integration tests.

[LindaSummer]

Hi Team,

Sorry for delaying this feature's implementation.

I kept the commit log since we will squash merging.
Maybe it can help new-commers if they meet similar problems as me for a new feature. 😄

Please give me some suggestions and help take a review.

There are still many parts need to be improved, and I will be very happy to try my best for any improvement. 😊

Best Regards,
Edward

[sonarqubecloud]

Quality Gate failed

Failed conditions
2 Security Hotspots
C Reliability Rating on New Code (required ≥ A)

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