Windows PowerShell port

This PR introduces a PowerShell port of the original bash script that can be run on Windows.

To run from a PowerShell console, simply:

	./bin/support-diagnostics.ps1

The script accepts all of the command line arguments that the original bash script accepts.

The output is a zip file instead of a tarball.  I also tried to keep variable names as similar as possible to the original script, as well as the general flow / order of operations in effort to make cross-maintenance a little easier.
Careful, if they set the output directory to a shared location, then this will suffer from the same problem as the Unix script.