Define a separate route and API for authentication (like giveth.io/v1/auth) on Gateway

[CarlosQ96]

To test the microservice:
Setup Nginx auth in the staging server so that requests arrive to the route serve.giveth.io/auth
Routes would temporality look like serve.giveth.io/auth/v1/authenticate
For testing initially.

Or directly setup a subdomain will be auth.giveth.io.