Remove crawler regex configuration, replace references to non-existent $ponydocsMediaWiki with $splunkMediaWiki

PonyDocs has a feature to allow internal search indexers to access preview and unreleased versions.

We used to allow access based on IP address or useragent.
Useragent is not secure, so this pull removes it.

We also had a number of bugs and other sloppiness around the configuration of the IP address which has been fixed.