Now that we have [PowerShell Core](https://github.com/powershell/powershell) the cross-plat version of PowerShell... it'd be really cool to have a badge that shows the OS's that your module works on.
On the PowerShell Gallery, users can do this by using the tags `Windows` `MacOS` `Linux`. In this PR, I use the PowerShell Gallery API to grab the tags from that package and display `windows` `macos` `linux` if they exist.
The result is:
which aligns with Conda and Cocoapods
The NuGet badge examples are straggling in all-badge-examples. Rather than move them as is, I thought it made more sense to refactor the services and see if they could be generated. I didn't take that on here; this is a straight rewrite of the badges. The old implementations were fairly difficult to follow. The new implementations are complicated too, though I hope much more readable.
Though the NuGet behaviors could be consolidated into a single flag, I split `withTenant` and `withFeed` into separate flags, thinking naming the behaviors makes the implementations easier to understand. I defaulted these to true, thinking that really this is really a MyGet implementation which is generalized to NuGet. Though maybe it makes more sense to have the MyGet style as the default. Probably it doesn't matter much either way.
I added a helper class ServiceUrlBuilder to construct the Shields service URL. It's useful in this complex case where the URL must be built up conditionally. This might be useful in a couple other places.
I also wrote a new service to handle the Powershell badges. They've diverged a little bit from the Nuget v2. There's a bit of shared code which I factored out.
If the XML Nuget APIs are more reliable, we could consider switching everything else over to them, though for now I would like to get this merged and get #2078 fixed.
Fix#2078
