Fix HTTP status of unauthorized requests

[DanLindeman]

Why

• The status codes from unauthorized requests currently return 500 with {message: null}
• 'Unauthorized' is a very specific message expected by the error handling pattern matching in lambda and gateway
• The expected response code of unauthorized http requests is 401 Unauthorized

How

• Instead of returning a more meaningful message we must raise Exceptions with exactly 'Unauthorized'

Side effects

• The formatter Black was used to make consistent quotation usage
• This is a half-way fix, ideally we need to be adjusting the authorizer to put error handling patterns and use custom Exceptions

[svdgraaf]

@DanLindeman I just released 0.10.0 with the 401 response. I also cleaned up the javascript file, added a eslint and flake8 config files so the style should always stay the same. Great work!

[DanLindeman]

Excellent! Thanks for merging it in and the quick turnaround time!