Add value set skipping index

[dai-chen]

Description

1. Add SkippingKind enum as more skipping algorithm added
2. Add ValueSet skipping strategy
   a. Rename from ValueList since Set is more accurate to express the value uniqueness in this skipping data structure
   b. More details in doc: https://github.com/dai-chen/sql-1/blob/add-value-list-index/flint/docs/index.md#feature-highlights

Issues Resolved

opensearch-project/opensearch-spark#2

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Merging #1708 (ef0f7e4) into feature/flint (e80cf9b) will not change coverage.
The diff coverage is n/a.

@@               Coverage Diff                @@
##             feature/flint    opensearch-project/sql#1708   +/-   ##
================================================
  Coverage            97.19%   97.19%           
  Complexity            4107     4107           
================================================
  Files                  371      371           
  Lines                10464    10464           
  Branches               706      706           
================================================
  Hits                 10170    10170           
  Misses                 287      287           
  Partials                 7        7           

Flag	Coverage Δ
sql-engine	97.19% <ø> (ø)

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