Upstreams + more flexible parameters

- Adding support for upstreams. Currently in nginx.conf, a potential improvement would be to put them under upstreams/ and then include that in nginx.conf or something similar.
- Locations are specified as a `location` list
- Server names can be specified as either a string or a list
- Updated templates
This would need to be updated to ANXS. Sorry for the inconvenience, but this is due to namespace clashes that occurred on galaxy.