Chore: Clean up new issue workflow

[nzakas]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

Clean up our new issue workflow.

What changes did you make? (Give an overview)

1. Removed the Question template (because we don't want people opening an issue for a question) and replaced it with a link to the Discussions section
2. Removed the Security template (because we don't want people opening an issue for security problems). GitHub already shows a link to the security policy when creating a new issue.
3. Removed the link for creating an RFC because we want people to file an issue first before creating an RFC.

Is there anything you'd like reviewers to focus on?

Do these changes make sense?

[snitin315]

Makes sense