Add self-contained remote Artemis image support

[JTNing]

Summary

• Extend the existing local Docker package so it can start Artemis from either a local checkout or the official remote image.
• Propagate the Artemis source commit and image digest into snapshot and package metadata.
• Generate self-contained MySQL/PostgreSQL Compose stacks with selection-aware CI profiles, startup/stop scripts, documentation, and regression coverage.
• Fix remote teardown by restoring the Compose interpolation paths required by docker compose down.

Motivation

This allows generated Docker demo packages to run without a local Artemis repository while preserving runtime provenance and the existing local-checkout workflow.

Validation

• ./gradlew test --rerun-tasks — 364 tests, 0 failures, 7 skipped.
• docker compose config --quiet passed for generated remote-image stacks.
• Remote-image startup and isolated stop-script behavior were manually verified.