Warn on missing docker config or .sock permissions

On some linux setups the .config file in the docker home will be empty and needs to have `{}` added, and by default Ubuntu (at a minimum) doesn't add the user to the docker group, so the .sock runtime file is similarly inaccessible. These two missing changes make docker actions within the extension silently fail. We should prompt the user when we can't reach these files to some basic debugging steps, such as ensuring a modern version of docker is installed, presence of unreachable file, and proper permissions set to take actions.