new wiki page: PowerDNS setup, moved content from README.md to new docs dir

Created new PowerDNS page explaining config needed to setup PowerDNS on Debian 7

Moved README content to new files in /docs
- docs/How-do-I-run-my-own.md
- docs/How-do-I-use-it.md
- docs/dot-bit-Domains-and-Identities.md