Make credentials more clear

[beckyjackson]

Currently, creating credentials is buried under cogs init. There should be a section at the beginning of the README that provides more details on creating the credentials.

[turbomam]

I can do this late this week or early next week.

I got COGS to work on my protected sheets by reading the init help and consulting this: https://developers.google.com/sheets/api/guides/authorizing

[turbomam]

Or I can do it now

[beckyjackson]

Thank you for writing that up @turbomam ! I consolidated some of the details to make it a bit shorter, but your text was a great starting point. Glad you were able to get COGS up and running, please let me know if you have any other questions or run into any problems 😄

[beckyjackson]

Resolved by #139