Configure client authentication

Summary:
This configuration is based on the PostgreSQL Docker image one,
with an extra entry to allow authenticated replication.

Ref T1791.

Test Plan: Build and test on Dwellers. Deploy on docker-002.

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1791

Differential Revision: https://devcentral.nasqueron.org/D2867