Add hello examples with new APIs

[nvkevlu]

Add hello examples with new APIs

Description

Add hello examples with new job and client APIs, re-based version of this: https://github.com/NVIDIA/NVFlare/pull/2723 but without deleting the previous hello examples for now. We need the current ones for CI, and we can still reorganize this.

Types of changes

• [x] Non-breaking change (fix or new feature that would not break existing functionality).
• [ ] Breaking change (fix or new feature that would cause existing functionality to change).
• [ ] New tests added to cover the changes.
• [ ] Quick tests passed locally by running ./runtest.sh.
• [ ] In-line docstrings updated.
• [ ] Documentation updated.

[chesterxgchen]

can we fix the CI/CD with new APIs ? if we have both them in the hello example folder it defeat the original purpose.

[YuanTingHsieh]

Because these are new styles of example that currently are not supported in CI.

I could just move all old hello examples to testing directory and change CI to that dir for testing. So it does not confuses users. Users will only see new style of examples.

[nvkevlu]

Because these are new styles of example that currently are not supported in CI.

I could just move all old hello examples to testing directory and change CI to that dir for testing. So it does not confuses users. Users will only see new style of examples.

I think that sounds good. I was looking into the CI and are we actually testing from hello examples from the examples directory or just using the configurations under tests/integration_test/data?

[nvkevlu]

I decided to move and keep the existing CI jobs out of the way in test/integration_test/data/test_configs/standalone_job/previous_jobs, and for the new Job API jobs, I did not export jobs because I thought it would create too much extra clutter in the beginning that may confuse and intimidate new users, and if they are ready to look into the job, they can run the export job command themself when they are ready to look at it.

[YuanTingHsieh]

Great PR with a lot of details, added some comments

[nvkevlu]

CI doesn't pass because we are adding new pages, and the link checker does not consider pages being added as existing

[YuanTingHsieh]

Ok we can merge this then make sure ci passing after this merge

[chesterxgchen]

let's do that, we might have to consolidate hello-world with getting started and removed some duplication, we could have done that before the conversion :-(