Description of changes

This PR:

• Adds Sybase support for DVT
• Add a limitations documentation page where we can build up a list of limitations
• Adds an internal test instance with Sybase ASE 16 and a full set of integration tests
• Adds retry logic for flaky test infrastructure (e.g. Db2 and Sybase)

In general I've referred to Sybase as Sybase ASE. There appears to be other flavours of Sybase out there (with different SQL/function support) but the customer interactions I've had have all related to Sybase ASE.

It's probably worth elaborating on Sybase limitations here:

• There is no SHA256 function available so we are restricted to concat and comp-fields row validation. (TODO create issue to explore custom UDF option and update text in registy.py)

Issues to be closed

Closes#1538

Checklist

• I have followed theCONTRIBUTING Guide.
• I have commented my code, particularly in hard-to-understand areas
• I have updated any relevant documentation to reflect my changes, if applicable
• I have added unit and/or integration tests relevant to my change as needed
• I have already checked locally that all unit tests and linting are passing (use thetests/local_check.sh script)
• I have manually executed end-to-end testing (E2E) with the affected databases/engines