Support sweeps in W&B

[dmcc]

Right now, sweeps are essentially done manually in Aeromancy. With #27 and some Aeromancy API updates, we could make sweeps better integrated in experiment trackers.

Proof of concept for retroactive sweep creation:

>>> sweep_id = wandb.sweep(project='...', sweep={'method': 'random', 'parameters': {'...': {'values': [1, 2, 3]}}}, prior_runs=['...'])

where prior_runs is a list of short run IDs (e.g., cmzbpa8q) -- not the full entity/project/cmzbpa8q path.