* 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
- build backend and frontend with cacheing using GHA cache)
- streamline frontend image to reduce layers
- setup local swarm with test/setup.sh script, wait for containers to init
- copy sample config files as default (add storages.sample.yaml)
- add initial backend test for logging in with default superadmin credentials via 127.0.0.1:9871
- must use 127.0.0.1 instead of localhost for accessing frontend container within action
