Add Auth0 Connection

[doheekim93]

Add an Auth0 connection on the Apple Developer side https://auth0.com/docs/connections/apple-siwa/set-up-apple?_ga=2.144576438.2000580528.1599009453-344154310.1590430631

Once this is setup, we can add Apple ID sign in on the backend (please reach out to relevant people for this!)

Please also refer to this ticket for more information