updates and upgrades for the static mirror

- Refactor configuration slightly for DRY
- Bind to a specific port per mirror rather than hostname based servers
- use X-Forwarded-For header to log real ip address
- Return 503 response for all URLs except:
  - Serve from mirror:
    - /packages
    - /simple
    - /serversig
    - /local-stats
    - /last-modified
  - Return 501:
    - /daytime