Add code generation and verification to PR builds

[nielspardon]

As identified here #114 (review) and here #113 (review) there currently is a risk that when the Git submodule for substrait gets updated that the protobuf, ANTLR and JSON schema code generation are not being executed.

We should try to see how we can reuse the ./.devcontainer/Dockerfile during the Github Actions build to create an environment with all the dependencies to allow us to run the code generation during a PR build.

We then would run the code generation within the container and afterswards check whether there are any uncommitted changes generated by the code generation and fail the build accordingly.

In order to achieve this we may need to change the JSON schema code generation to not add a timestamp into the generated code.

[nielspardon]

completed via #114