- adapt nginx config to work both in docker and k8s, using env vars to set urls
backend: additional fixes:
- use env vars with nginx config
- fix settings api route
- when sending e-mail, use the Host header for verification urls when available
- prepare Dockerfile with full build from scratch in image, (disabled 'yarn install' for faster builds for now)
- fix accept invite api for existing user to /archives/accept-invite/{token}