Add authentication

[amaury1093]

• [x] ~Login with username/password.~ Replaced with Auth0.
• [x] ~Sign up with username/password.~ Replaced with Auth0.
• [x] ~Improve the design a bit.~ Use Auth0's design
• [x] Save access token locally on the frontend, i.e. "remember me on this computer" feature.
• [x] Implement Auth0 login flow.
• [x] User profile (e.g. user picture) is handled by Auth0.

So in this PR you can login/logout with Github or email/password as much as you want. As a small bonus, I added the draw controls, so you can draw a polygon, and its geojson will show in the console.

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[amaury1093]

Added codacy. The errors here are linting errors, no big deal. I disabled codacy's linting in the next PR, that one's green.