Pytorch-lightning: Using multiple loggers

[ceyzaguirre4]

Describe the solution you'd like
Trainer could receive a list of loggers instead of only one, all loggers would be called at the appropriate times.

Describe alternatives you've considered
Alternatively could create a customLogger that logged the information to all relevant destinations (eg. tensorboard AND mlflow)

[neggert]

What about using the existing base logger to create a composite logger that takes a list of loggers and calls them all?

[williamFalcon]

Would it be helpful to add an example of this to the docs?