Flask defaults, some reduced coupling & cleaning up

[monneyboi]

This PR refactors some of the view logic to more closely follow the flask documentation / defaults.

It looks like a lot, but not much is going on:

• require was dropped in favor of abort
• Some HTTP 403 codes were changed to HTTP 401 where that made sense.
• jsonify and related calls were dropped in favor of a JSONProvider
• A test was added for JSONP functionality
• Code was localized from general utils to local files where possible
• Unused code was removed

This was done with the intention of reducing coupling, side-effects, and making the code more understandable for newcomers.

[stchris]

I started reviewing this but I find it really hard with all the things going on. I will need some more time. Perhaps we can focus on potentially just doing one thing per PR in the future, @monneyboi ?

[monneyboi]

Perhaps we can focus on potentially just doing one thing per PR in the future, @monneyboi ?

Yes sorry, i can imagine. I can also split this one up if that helps?

[Rosencrantz]

@monneyboi If you'd be willing to slit this up it'll making merging and releasing it a lot faster/easier

[Rosencrantz]

ping @monneyboi