[Github Community] Add a .github folder to create issue templates

Summary:
Inspired by Issac and other github open souce, I suggest creating templates for issues and feature request.

• Issue templates help contributors describe their context for bug or feature requested clearly.
• Templates serve as prompt for issue authors, not requirements.
• It should helpful to understand dagit UI issues especially.

We can also add links of dagster website repo and github discussion on the landing page of creating new issues to promote adding user logos,
writing posts and discussion.

Test Plan: Can only see the results after land on github

Reviewers: max, alangenfeld

Reviewed By: alangenfeld

Subscribers: dish, nate

Differential Revision: https://dagster.phacility.com/D5112