Rails/Node: Installing PostgreSQL on MacOS using Postgres.app

[crespire]

Because

Postgres.app makes managing and installing PSQL and its associated tooling much easier on macOS, and lets us also change versions of PSQL easily.

This PR

• Updates instructions to use Postgres.app to install PostgreSQL on MacOS on the Rails path
• Replicates changes to the NodeJS path lesson

This PR is in draft, as I have an outstanding question on the related issue about how we should set up local authentication.

Issue

Closes #29164

Additional Information

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