Stop using github auth and switch to oauth

[greggman]

I'm sure this will fall on deaf ears but whatever, I'm reporting it.

No developer that cares about security should ever be using github auth which asks for the most ridiculous permissions ever

No, you do not have permission to act on my behalf and this site should not need that permission. If you clicked to allow it you're effectively giving this site permission to hack all of your repos. I know that's not actually what happens but nothing about the wording makes that clear and so following the wording you are giving permission to edit all of your repos which is insanely not security conscious.

Please stop using github auth or at least provide other means to report issues.

[karlcow]

Paper trail:

• Provide a way to report issues without requiring GitHub auth. #46
• Excessive permissions required to file a bug using Github #655
• GitHub App permission #3626
• Github app permission does not affirmatively provide scope of permission #3722

Also related dear-github/dear-github#113