[db engine] Add support for Elasticsearch

[dpgaspar]

CATEGORY

Choose one

• Bug Fix
• Enhancement (new features, refinement)
• Refactor
• Add tests
• Build / Development Environment
• Documentation

SUMMARY

Add support for Elasticsearch. Includes a specific engine spec, most work done upstream on elasticsearch-dbapi (https://github.com/preset-io/elasticsearch-dbapi) that implements a PEP-249 DBAPI and SQLAlchemy dialect that "queries" X-Pack SQL (Limited to no support for opendistro yet)

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Example Dashboard:

SQLLab:

TEST PLAN

ADDITIONAL INFORMATION

• Has associated issue: +1 to addition of Elasticsearch support. #5984
• Changes UI
• Requires DB Migration.
• Confirm DB Migration upgrade and downgrade tested.
• Introduces new feature or API
• Removes existing feature or API

REVIEWERS

[codecov-io]

Codecov Report

Merging #8441 into master will decrease coverage by 1.08%.
The diff coverage is 81.25%.

@@            Coverage Diff             @@
##           master    #8441      +/-   ##
==========================================
- Coverage   67.61%   66.53%   -1.09%     
==========================================
  Files         448      449       +1     
  Lines       22486    22502      +16     
  Branches     2364     2364              
==========================================
- Hits        15204    14971     -233     
- Misses       7144     7393     +249     
  Partials      138      138

Impacted Files	Coverage Δ
superset/db_engine_specs/elasticsearch.py	81.25% <81.25%> (ø)
superset/db_engine_specs/presto.py	22.43% <0%> (-42.49%)	⬇️
superset/db_engine_specs/pinot.py	43.33% <0%> (-26.67%)	⬇️
superset/db_engine_specs/hive.py	27.85% <0%> (-12.33%)	⬇️
superset/db_engine_specs/mssql.py	58.33% <0%> (-11.12%)	⬇️
superset/db_engine_specs/postgres.py	83.87% <0%> (-9.68%)	⬇️
superset/db_engine_specs/bigquery.py	45.07% <0%> (-8.46%)	⬇️
superset/models/sql_types/presto_sql_types.py	65.51% <0%> (-6.9%)	⬇️
superset/db_engine_specs/base.py	80.73% <0%> (-4.66%)	⬇️
superset/sql_parse.py	96.12% <0%> (-3.11%)	⬇️
... and 1 more

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[villebro]

Awesome! 🎉

[mistercrunch]

❤️

[dioptre]

Wondering if anyone managed to get this working with opendistro?

preset-io/elasticsearch-dbapi#31