Implement discords OAuth API

[surajkumar]

As a user I want to...

be able to call the OAuth endpoints

So that...

I can perform actions using my discord account using a discord bot

Context

Discord provides a rich set of APIs for interacting with channels in a discord server. We should implement all these endpoints. This ticket covers only the OAuth endpoints. https://discord.com/developers/docs/topics/oauth2

This is not a MVP

Acceptance Criteria

GIVEN a user wants the bot to perform actions on their account
THEN the specified action should be executed with sufficent error logging in place

This PR should also include the rest of the oAuth related endpoints such as the one below, scour the docs for them if needed:

• https://discord.com/developers/docs/resources/guild#add-guild-member