Migrate Dockerfiles to source repos with GHCR publishing

[thvl3]

Move Dockerfiles from this playbook to their respective source repositories and set up GitHub Actions to publish images to GitHub Container Registry (GHCR).

Current State

Dockerfiles for bar-db and bar-live-services live in roles/live-srv/files/ and images are built on the target server during deployment.

Proposed Changes

bar-db repository

• Add Dockerfile to https://github.com/beyond-all-reason/bar-db
• Add GitHub Actions workflow to build and push to ghcr.io/beyond-all-reason/bar-db
• Tag images on release/commit

bar-live-services repository

• Add Dockerfile to https://github.com/beyond-all-reason/bar-live-services
• Add GitHub Actions workflow to build and push to ghcr.io/beyond-all-reason/bar-live-services
• Tag images on release/commit

This playbook

• Remove local Dockerfiles
• Update containers.yml to pull from GHCR instead of building locally
• Add image version variables to group_vars