Remove super outdated Wiki page

All of those can and should be deleted.
Some where still linked in coho docs, others turn up when googling for stuff :/

Now in Coho docs:

• https://wiki.apache.org/cordova/IOSReleaseChecklist
• https://wiki.apache.org/cordova/iOSManualTests

Outdated and wrong:

• https://wiki.apache.org/cordova/Platform%20Engine
• https://wiki.apache.org/cordova/CordovaCLIManualTests

Meta stuff:

• https://wiki.apache.org/cordova/ReportingBugs
• https://wiki.apache.org/cordova/ContributorsGroup
• https://wiki.apache.org/cordova/IRC%20Communication