Replace issue template with YAML issue forms

[thevurv]

Github has more powerful YAML issue templates which have more flexibility compared to just a default blob of text.

https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/syntax-for-issue-forms

[Denneisk]

I don't understand why the unnecessary parts weren't commented on the existing forms.

[Denneisk]

Guess it's a decent litmus test at least.