Add Dockerfiles to qa citus packages

[m3hm3t]

No description provided.

[onurctirtir]

why can we have the database already initialized?

[m3hm3t]

To make this more robust, we can check for pg_control in /var/lib/postgresql/${PG_MAJOR}/main/global/, which ensures that the database directory is actually valid before skipping initialization.

RUN if [ ! -f "/var/lib/postgresql/${PG_MAJOR}/main/global/pg_control" ]; then \
       echo "Initializing new PostgreSQL database..."; \
       /usr/lib/postgresql/${PG_MAJOR}/bin/initdb -D /var/lib/postgresql/${PG_MAJOR}/main; \
    else \
       echo "Existing PostgreSQL database detected, skipping initdb."; \
    fi

Let me know if you think this approach works, and I can push an update!