Restructuring training visualization and adding support for Weights & Biases Logger

[manangoel99]

This PR redesigns the logging system in GAN without changing any of the console logging. The proposed change is to have a BaseLogger class from which new loggers can inherit. This includes the VisualDL logger, the new Weights & Biases Logger and any new custom loggers that might be added later. Using the W&B Logger would be really easy for users. The only requirement is to set enable_wandb:True in the config.yml file. To add any other wandb related arguments like project name, entity name and so on, the users can add the wandb key. For example: This leads to all the training metrics being logged to W&B. The dashboard:

The models at every model saving step and evaluation step are also logged to the W&B run with the appropriate tags and metadata.

The dashboard is available here

[manangoel99]

@LielinJiang @lijianshe02 I was wondering if it was possible to get some feedback

[manangoel99]

@LielinJiang @LielinJiang I would love some feedback on this whenever you have the time

[manangoel99]

Hi @LielinJiang @lijianshe02 It would be awesome if I could get this reviewed whenever possible

[LielinJiang]

Very glad to receive your pull request, we will review it as soon as possible

[jerrywgz]

Thx for your contribution. Could you add the function to PaddleMIX models https://github.com/PaddlePaddle/PaddleMIX/tree/develop