feat(other): major improvement of deployment

[roschaefer]

Motivation

Kubernetes:

• backend becomes a statefulset (exclusive volume mount) See: https://spacelift.io/blog/statefulset-vs-deployment
• implement neo4j backup with job

Docker:

• consistent targets across all dockerfiles
• remove redundant labels
• remove unnecessary build args
• remove obsolete networks
• remove development dependencies for production

Rebranding:

• add image tags for local tagging and pulling
• use Github's docker build workflows
• use Github container registry
• ONBUILD to simplify caller Dockerfiles
• docker compose for branding

Tooling:

• same node --version as in dockerfile

Docs:

• missing step in README.md