[WIP] Make authMiddleware an async function

[Craaftx]

ℹ️ Link to issue #13

TODO :

• authMiddleware line 109 should be an async function ✔
• rewrite promise .then using await ✔
• callback should be called with await
• line 72, 73 use await/async ✔

[Craaftx]

I think it's done.

But for this point : (callback should be called with await), I didn't find on the net answers about the fact that an Async function can not execute into the parameters of a function.
Like in this case :

zoauthRouter.js - line 70
[...]
root.methods[method].call(
      p,
      async (req, res, next) => {
        await root.authMiddleware(req, res, next, authCb);
      },
[...]

So i think it's ok like this.

What do you think @willdurand ?