docs: Documentation and samples updates

[nj1973]

Description of changes

Just fixing a missing documentation entry and a few sample file issues.

Issues to be closed

• Closes BigQuery connection option --client-project-id is missing from docs #1676
• Closes Fix mistakes in sample SQL Server Dockerfile #1672

Checklist

• I have followed the CONTRIBUTING 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 the tests/local_check.sh script)
• I have manually executed end-to-end testing (E2E) with the affected databases/engines

[nj1973]

/gcbrun

[nehanene15]

We should call this the 'quota project id'. The compute/slots will still be billed to the project specified by --project-id. Could reference this in the docs - https://docs.cloud.google.com/docs/quotas/quota-project

[nj1973]

But this project_id is also used to define the client here:

professional-services-data-validator/data_validation/clients.py

Line 122 in 48f9ad0

project=effective_project,

Which I believe ensures compute is assigned to that project too.

This allows users to have their billing/compute in a different project to the one that houses the data.

Or did I misunderstand how this works?