feat(framework) Enable configuring the simulation backend via flwr run

[jafermarq]

If the [federations] section in a pyproject.toml contains options.backend components, these will be passed to flower-simulation via the existing --backend-config CLI argument. This can be used to parameterize the simulation backend, for example to control the CPU/GPU resources a ClientApp uses.

[tool.flwr.federations.remote-A100]
address = "1.2.3.4:5678"  # SuperExec address
options.backend.client-resources.num-cpus = 4
options.backend.client-resources.num-gpus = 0.25
options.backend.init-args.log-to-driver = false

The above content of options.backend will be parsed into:

{'client-resources': {'num-cpus': 4, 'num-gpus': 0.25}, 'init-args': {'log-to-driver': False}}

and eventually passed to flower-simulation. At the entry point of flower-simulation from the CLI. the - will be replaced with _.

Note

Specifying options.backend... is entirely optional.