Add a rate limits to the Google drive API and catch rate limit errors

[BenCookie95]

Summary

• Create a wrapper for all the Google API calls.
• Added a rate limiter for the Google Drive API. The activity, sheets, docs and slides api do not have rate limiter because it's very unlikely they will cause an issue but I still catch any rate limit errors and block people for a period of time from making requests when they have exceeded any google rate limits.
• Created a method in order to parse rate limit errors from Google.
• Added 2 configs for configuring the rate limit, we cannot read the limits from Google using their API.
• Moved some slash commands into command.go because the root server directory was cluttered with files containing 1 function.
• Better use of context throughout.

TODO in another PR

• Fix unbounded calls to the activity API

[fmartingr]

Thank you for the refactor and all the comments, makes it easier to follow around. 👍

[wiggin77]

LGTM 👍