Move uwsgi under var run to be restart save

This moves the uwsgi.socket under /var/run/uwsgi/.

This enables the docker container to be restarted without having bind issues.

Though it needs to create a readwrite file system under /var/run with -v /var/run/

Please test it, if it fits all the needs.

I haven't run this container in production and not a complete test environment. Though I have verified that the container is able to restart by running docker restart and checking the logs.