shayonj/pg_easy_replicate: Easily setup logical replication and switchover to new database with minimal downtime

pg_easy_replicate is a CLI orchestrator tool that simplifies the process of setting up logical replication between two PostgreSQL databases. pg_easy_replicate also supports switchover. After the source (primary database) is fully replicated, pg_easy_replicate puts it into read-only mode and via logical replication flushes all data to the new target database. This ensures zero data loss and minimal downtime for the application. This method can be useful for performing minimal downtime (up to <1min, depending) major version upgrades between a Blue/Green PostgreSQL database setup, load testing and other similar use cases.