Eng 2698 Implement v2 api framework

[likawind]

Describe your changes and why you are making these changes

This PR implement foundations of RTK Query framework together with a basic WorkflowGet query. The RTK implementation is based on prototype in #1130 .

• All v2 routes will have v2 prefix in route name so that they don't conflict with any existing routes, and we can safely merge them to main.
• We now have clear mapping between UI routes / responses and backend handler / responses, which are also explicitly stated in comments.
• In v2, we name routes by resourceMethod so that the same resource is naturally grouped together by file ordering

Related issue number (if any)

Loom demo (if any)

Checklist before requesting a review

• I have created a descriptive PR title. The PR title should complete the sentence "This PR...".
• I have performed a self-review of my code.
• I have included a small demo of the changes. For the UI, this would be a screenshot or a Loom video.
• If this is a new feature, I have added unit tests and integration tests.
• I have run the integration tests locally and they are passing.
• I have run the linter script locally (See python3 scripts/run_linters.py -h for usage).
• All features on the UI continue to work correctly.
• Added one of the following CI labels:
  • run_integration_test: Runs integration tests
  • skip_integration_test: Skips integration tests (Should be used when changes are ONLY documentation/UI)

[kenxu95]

The backend changes look good to me, as well as WorkflowGet.tsx.