Add self to CFGDenoiserParams

[continue-revolution]

Description

This PR aim for adding CFGDenoiser itself as a parameter inside CFGDenoiserParams so that I am able to retrieve my script arguments and something else if I want to add a callback.

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests

[AUTOMATIC1111]

Some extensions use this class to in their own code, so adding it like this will break them. Let's make the denoiser argument None by default.