Create an omnisci backend for sqlalchemy

[xmnlab]

Justification

Describe the problem that should be resolved

Create an initial omnisci backend for sqlalchemy.

Request (General goal)

Describe the general goal for this request. What is the high level objective of the work? What is the outcome? What does success look like?

• Connect to a OmniSci instance using sqlalchemy.
• Use it also with Apache Superset

Stakeholders

Who are the stakeholders for the different pieces that might need to clarify things

@mflaxman10

Technical Specification

Describe all the items needed to conclude this task What should the final state look like?

• It should work for the basic types and functions.
• As sqlalchemy doesn't work with geo spatial types (it should be done using geoalchemy2) it will not have this implementation for now (need more investigation).
• It should have a good test coverage to ensure the results

References

Add any reference resource that can help to conclude this task

There is an initial implementation that should be used as reference:

• https://community.omnisci.com/t/apache-superset-and-sql-alchemy-usage-with-omniscidb/2633

There is an initial PR, the implementation and problems would be discussed there:

• https://github.com/omnisci/sqlalchemy-omnisci/pull/1

[xmnlab]

@mflaxman10 as the initial PR was already merged I am closing this PR for now (let me know if you prefer this issue opened). I am opening specific issues on https://github.com/omnisci/sqlalchemy-omnisci so we can track all steps needed to have the first release. thanks