Integration of wandb sweeps for parameter tuning

[jhaux]

Wandb is already in use for logging, but there are a lot of useful features we are currently not supporting out of the box. Your project would be to make it easy for edflow users to do hyper parameter sweeps, that would potentially use wandb in the background.

[jhaux]

This would be a first step in the direction of #50.

[jhaux]

Implemented in #254