[Backport 2.x] Enable PPL lang and add datasource to async query API

[opensearch-trigger-bot]

Backport ea2ed26 from #2187.

[codecov]

Codecov Report

Merging #2195 (e3e1337) into 2.x (8c5ecba) will decrease coverage by 0.02%.
The diff coverage is 77.77%.

@@             Coverage Diff              @@
##                2.x    #2195      +/-   ##
============================================
- Coverage     96.61%   96.59%   -0.02%     
+ Complexity     4754     4752       -2     
============================================
  Files           437      437              
  Lines         12702    12693       -9     
  Branches        861      859       -2     
============================================
- Hits          12272    12261      -11     
- Misses          420      422       +2     
  Partials         10       10              

Flag	Coverage Δ
sql-engine	96.59% <77.77%> (-0.02%)	⬇️

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Files	Coverage Δ
...park/asyncquery/AsyncQueryExecutorServiceImpl.java	100.00% <100.00%> (ø)
...rch/sql/spark/dispatcher/SparkQueryDispatcher.java	100.00% <100.00%> (ø)
.../sql/spark/rest/model/CreateAsyncQueryRequest.java	22.72% <45.45%> (+22.72%)	⬆️