* backend: refactor swarm support to also support podman (#260)
- implement podman support as subclass of swarm deployment
- podman is used when 'RUNTIME=podman' env var is set
- podman socket is mapped instead of docker socket
- podman-compose is used instead of docker-compose (though docker-compose works with podman, it does not support secrets, but podman-compose does)
- separate cli utils into SwarmRunner and PodmanRunner which extends it
- using config.yaml and config.env, both copied from sample versions
- work on simplifying config: add docker-compose.podman.yml and docker-compose.swarm.yml and signing and debug configs in ./configs
- add {build,run,stop}-{swarm,podman}.sh in scripts dir
- add init-configs, only copy if configs don't exist
- build local image use current version of podman, to support both podman 3.x and 4.x
- additional fixes for after testing podman on centos
- docs: update Deployment.md to cover swarm, podman, k8s deployment
- add custom init script for ./docker-entrypoint.d/ to setup resolver from local /etc/resolv.conf
- custom init script also removes default.conf, and removes minio route if NO_MINIO_ROUTE=1 is set
- assign template vars to nginx vars to avoid conflicts when interpolating
- k8s: remove initContainers and volumes, now handled via custom init script in image
