Improvements to oauth.py

[nwunderly]

oauth.py is a bit of a mess at the moment. It's meant to be an internal class, and it's essentially just a port of a requests-based implementation that I pulled from a Gist a while ago. It's in desperate need of some love.

Any improvements to the file are welcome, and will be accepted as PRs. This issue will remain open until the file is fully improved.

Some ideas:

• rewrite internal functions that aren't used by starlette-discord to fix bugs we've missed
• reformat or rewrite documentation for the class and its methods (see #20)
• general QOL changes to the class or its attributes/methods (breaking API changes will need to be justified and documented)

This is a bit of a more complicated task. It's likely something I'll revisit in the coming months, and (if necessary) just rewrite from scratch myself. That said, any improvements to library internals are always welcome.

Happy Hacktoberfest!! :smile:

[akhilsharmaa]

This seems interesting I would like to work on this issue.