Leveraged `clap` library to configure the service via command line args. I find this extremely useful when running the service in various environments: nix or docker, localstack/sandbox or real aws, or together with other services outside docker.
Added possibility to configure the following:
- gRPC listening port (defaults to 50051)
- to run in sandbox mode (previously (and still) available via the `COMM_SERVICES_SANDBOX` env var)
- localstack url (useful because it differs inside/outside docker). Defaults to the docker-correct one
- blob service url (also differs inside/outside docker). Defaults to the docker-correct one.
Related linear issue (for blob service, but the same applies here): https://linear.app/comm/issue/ENG-2310/make-blob-service-configurable
Depends on D5843