Add Facebook login to FTW

[OtterleyW]

This is a base branch for adding a Facebook login. On the high level this PR contains the following changes:

Generic:

• New env variables REACT_APP_FACEBOOK_APP_ID and FACEBOOK_APP_SECRET. The Facebook app id must be exposed to the frontend (using prefix REACT_APP_) so that we can determine if the Facebook login should be enabled or not.
• New cookies st-authinfo and st-autherror are used to store information. The expiration time for both cookies is 15 minutes.

Server:

• New endpoints createUserWithIdp and loginWithIdp - for using these, you need the latest version of sharetribe-flex-sdk
• Add Passport.js library for authenticating
• Use Passport's Facebook strategy to authenticate with Facebook. New routes auth/facebook and auth/facebook/callback

AuthenticationPage:

• Add button for logging in or signing up with Facebook and new function authWithFacebook
• Add new ConfirmForm form confirming information fetched from the identity provider (IdP, e.g. Facebook)
• Read information about loginWithIdp call from cookies

Button:

• Add new variant for the social login button

CheckoutPage and ListingPage:

• Add new parameter saveToSessionStorage to setInitialValues function so that we can store initial values to session storage before user is redirected to Facebook login. This enables redirecting user directly to CheckoutPage after authenticating from ListingPage

ContactDetailsPage and PasswordChangePage:

• Add reset password link to the pages where the current password is required (e.g. updating email). When signing up with IdP (e.g. Facebook), the user doesn't have an existing password so they first need to create one by going through the reset password flow.

How the Flow works in FTW

Log in with Facebook

Sign up with Facebook

This can be merged after the following parts have been completed:

• authWithIdp and createWithIdp endpoints to server (Add idp endpoints to FTW server #1365)
• Facebook login (Add Facebook login #1366)
• Add password reset links (Add password reset link #1367)

[feorgie]

can I confirm, Is this a typo?

[OtterleyW]

@feorgie yes that's a typo, it should be confirmError. Thanks for letting us know!

[feorgie]

no problem!