Add support for Category Forms on GitHub Discussions 🗨️ 

### Type of issue

Feature Request

### Description

They are similar to Issue Forms, just for GitHub Discussions.

Announced on GitHub Blog - https://github.blog/changelog/2023-02-03-category-forms-on-github-discussions/

![image](https://user-images.githubusercontent.com/2879818/217050605-37a9c3fd-7d4b-46f7-b8f9-c11d9b0369f7.png)


### Describe the solution you'd like

_No response_