add DCGAN

### Search before asking

- [X] I have searched the Roboflow Notebooks [issues](https://github.com/roboflow-ai/notebooks/issues) and found no similar bug report.


### Description

I want to add DCGAN to the notebooks list. DCGAN can be used to generate synthetic data.

### Additional

_No response_

### Are you willing to submit a PR?

- [X] Yes I'd like to help by submitting a PR!