Flower Baseline: FedAvg MNIST

[charlesbvll]

What does this implement/fix? Explain your changes.

Adds a new baseline for MNIST using a CNN in a federated setting.

[charlesbvll]

@danieljanes What I've already tried and tested for the mypy error :
(note that everything is working with Python, the error only pops up with mypy)

• After import dataset, dir(dataset) contains load_datasets, as expected, but mypy doesn't seem to recognize it
• Replacing import dataset and dataset.load_datasets by from dataset import load_datasets
• Replacing import dataset by import dataset as dataset or replacing from dataset import load_datasets by from dataset import load_datasets as load_datasets
• Playing around with the __init__.py even though all the files are in the same directory, this could be where I could have missed something

[charlesbvll]

@danieljanes What I've already tried and tested for the mypy error : (note that everything is working with Python, the error only pops up with mypy)

• After import dataset, dir(dataset) contains load_datasets, as expected, but mypy doesn't seem to recognize it
• Replacing import dataset and dataset.load_datasets by from dataset import load_datasets
• Replacing import dataset by import dataset as dataset or replacing from dataset import load_datasets by from dataset import load_datasets as load_datasets
• Playing around with the __init__.py even though all the files are in the same directory, this could be where I could have missed something

I just changed the name of the dataset.py file and it worked, mypy probably had some collision issue with the dataset name.

[danieljanes]

Looks good overall, I left a few comments on some details. In addition to that:

1. Remove the .5 from the distributed validation plot
2. Add two empty lines after each module docstring (before the imports)
3. Add tests, esp. for model and dataset