Platform support policy proposal

There is a fair amount of confusion about the specific operating system platforms, platform versions, etc. that Chef Software, Inc. supports for its products. This RFC will clarify this by calling out the individual operating systems and their releases as explicitly supported or not.
@juliandunn, surely in 11 months we will be discussing Chef 13 and dropping FreeBSD 8 support. I cannot measure the required infrastructure work, but considering that the EOL of other platform versions below is closer, I do not see this as crazy. All this taking into account that it already seems to work on FreeBSD 8. Of course, if the work involved is very large, it's not worth it.