Implement features for a new database

[darrencomeau]

consider making abstract methods ANSI SQL compliant and use an interface which includes those methods.

This would be the framework for database interoperability.

Anything which couldn't be written in ANSI SQL would need to be implemented in individual concrete database classes and a test framework would have to be updated when moving from one to the other.

If some databases have similar capabilities then a new interface with those capabilities could be shared

[darrencomeau]

NB, the interface isn't ANSI SQL compliant, the database is.

[darrencomeau]

To do this justice, would require automated tests and for that I would need a database engine available.

My current CI pipeline uses Azure DevOps. For an MSSQL database it is easy as they supply the cutdown database engine found with Visual Studio - LocalDB.

For anything else such as MySQL, Oracle or Postgres I would need to provision my own build agent.

Will take this out of the 1.0.0 milestone and hope to include this as demand grows.