Allow for multiple farms to be created from one solution with different vmsizes

[robdmoore]

This would allow people to have a test web farm and prod web farm (etc.) using a single solution. This allows for different vm sizes as well as different certificates.

Add the ability to XDT transform the csdef file for different versions (tie to the cscfg file they use? e.g. Cloud, Local, etc.) if a PowerShell command is entered.into the NuGet Console.

I have some ideas and sample code for how to perform the XDT so if someone feels like grabbing this then probably best to start a conversation here.