Add Flint describe index SQL support

[dai-chen]

Description

Add DESCRIBE/DESC SKIPPING INDEX statement. The skip type name below may be changed in #1800

Example: (Later will add to doctest)

$ spark-sql --hiveconf hive.cli.print.header=true

spark-sql> desc skipping index on http_logs;
indexed_col_name	data_type	skip_type
year	int	Partition
month	int	Partition
day	int	Partition
status	int	ValuesSet

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

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #1785 (807a1be) into feature/flint (ae3389d) will not change coverage.
The diff coverage is n/a.

@@               Coverage Diff                @@
##             feature/flint    opensearch-project/sql#1785   +/-   ##
================================================
  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)

Flags with carried forward coverage won't be shown. Click here to find out more.