Add Issue Templates (#4021)

Add issue templates for
- bug reports
- feature suggestions
- documentation
and a link to the discord for general discussion.

Open to other suggestions here. Could also add another "Other" template
with just a raw text box if we think this is too restrictive


<img width="1464" alt="image"
src="https://user-images.githubusercontent.com/130414180/236115358-e603bcbe-282c-40c7-82eb-905eb93ccec0.png">