refactor(baselines) Upgrade FedProx Baselne to new flwr format

[maddox-j]

Issue

Description

This PR upgrades the existing FedProx baseline from the previous flwr format to the new version.
Specifically:

1. Removed hydra library dependency
2. Adapted existing configuration files into pyproject.toml format
3. Use of Flower ClientApp and ServerApp
4. Populate dataset.py file to use flwr-datasets with DistributionPartitioner instead of manual handling.
5. Saving of results to disk by overloading the Server class definition.
6. Update README.md with steps to run baseline simulation through flwr run .

Related issues/PRs

N/A

Proposal

Explanation

This makes the FedProx baseline consistent with the current flwr version.

Checklist

• Implement proposed change
• Write tests
• Update documentation
• Make CI checks pass
• Ping maintainers on Slack (channel #contributions)

Any other comments?

N/A

[jafermarq]

Hey @maddox-j , this looks pretty good!! I added a few minor comments below.

I was able to run all the experiments running your script but then it seems the notebook ins't creating the plots. I believe some parts need (maybe just the process_data() function) adjustments since the results structure is different since we aren't using Hydra's --multirun anymore.

[maddox-j]

@jafermarq Thanks for all the comments. I have resolved your comments in one commit so that we keep the history a bit neater.

With reference to the notebook: I did make these function changes initially. I added a fixed path to the results in the notebook now in case this was the error. :)

[jafermarq]

@maddox-j , great to see FedProx running via flwr run 🚀