Authentication: auth middleware

[Austin2Shih]

• Build out some util functions in /src/utils/authToken.ts
• Build out createToken(data) --> {ok: bool, body: token?, error: error?} token or error are null depending on ok or not.
• Build out verifyToken(token) --> {ok: bool, body: decodedToken?, error: error?}
• From the middleware (right now it says something like token: req.headers.token as string. We want our middleware to be a function that takes in (req, res) => and takes the req to get cookies and have context.auth = verifyToken(token from cookie).
• We also want our context to pass in res so we can access context.res so we can set cookies with a Login/Register mutation.

[random-logic]

Submitted PR.