Misc style improvements to client metadata, unit test setup, and computation speed calculation

[ewenw]

• Fix code styling of client metadata related files

• Add option to calculate training task duration to draw computation speed from lognormal distribution

• Add pytest unit testing setup

• Make openai gym dependency optional based on RL task

• [x] I've included any doc changes needed for https://fedscale.readthedocs.io/en/latest/

• [x] I've made sure the following tests are passing.

• Testing Configurations

  • [x] Dry Run (20 training rounds & 1 evaluation round)
  • [x] Cifar 10 (20 training rounds & 1 evaluation round)
  • [x] Femnist (20 training rounds & 1 evaluation round)

[fanlai0990]

Thank you so much for contributing to FedScale. Everything looks perfect, and we learn quite a lot from you. :P