updates and upgrades for the static mirror

- Refactor configuration slightly for DRY
- Bind to a specific port per mirror rather than hostname based servers
- Return 503 response for all URLs except:
  - Serve from mirror:
    - /packages
    - /simple
    - /serversig
    - /local-stats
    - /last-modified
  - Return 501:
    - /daytime
optimize nginx location matching
whitespace
match mirror directories with ^~
log real ip addresses that hit mirror

this will allow us to see the approximate location of originating requests that hit the static mirror
Revert "match mirror directories with ^~"

This reverts commit fe5af36aa087fd98ee23ce15be86296829bfc50c.
Merge pull request #23 from python/mirror-fixups

updates and upgrades for the static mirror