Detect VMWare and display warning in Administration Console

Running on VMWare or other virtual environments has begun to become more popular. Confluence does not support VM, but often customers are not aware of this. The particularly sneaky part of this is that many configurations will run fine up to a certain point; the performance problems that can happen are unpredictable.

CONF-11301 is about clarifying when and why performance issues happen with virtual environments. This is a separate request, to detect that the OS is virtual and throw a warning, like the server base URL and XML backup warnings.

I don't know how to detect VM at an OS level - it seems tricky as VM providers don't necessarily provide an easy way to destinguish, at least not a java system property. There are a few forums, like this.