Support for LOCALSTACK_HOST, EDGE_PORT and USE_SSL

[Blind-Striker]

The following env variables should override ConfigOptions filled by appsettings.json:

• LOCALSTACK_HOST: Set the hostname for the LocalStack instance. Useful when you have
  LocalStack bound to a different host (e.g., within docker-compose).
• EDGE_PORT: Port number to use when connecting to LocalStack services. Defaults to 4566.
• USE_SSL: Whether to use https endpoint URLs. Defaults to false.