Replaces the paywalled bitnamilegacy app with the official discourse/discourse
image behind Traefik. DB is reused as-is; uploads migrate from the legacy
bitnami volume idempotently. The wrapper entrypoint injects the db_password and
smtp_password secrets (the official image has no *_FILE support). SMTP env vars
are renamed to the official names; release notes cover the migration.
Recipe 0.8.1+3.5.0 -> 1.0.0+3.5.3 (major: new image, env/volume/port changes).
