Better default checkpoint saving path

[APassbyDreg]

Usually, when I develop a model, a config file is modified many times to start different experiments. Currently, the checkpoints are saved to the default work directory by default. The folder looks like this:

config_name/
- timestamp 1/
  - [logs]
- timestamp 2/
  - [logs]
- epoch_xx.pth

In this case, it's hard to identify the experiment that generates the checkpoint, and later experiments can overwrite the previous checkpoint.

I suppose that saving the checkpoint to the experiment directory by default is a better idea.

[APassbyDreg]

Also, I think that the merged config file should be saved per experiment by default.

[zhouzaida]

Hi @APassbyDreg , it is recommended to use different config names for different experiments.