DotUninstall, a cross platform UI version of this tool

[lextm]

I built a minimalist UI for this tool using Uno a few weeks ago, and after a few iterations it is now mature enough to be announced here for more audience.

It relies on the same detection/uninstall logic from this repo (inherited via submodule), but also enriches the display by pulling down .NET metadata from builds.dotnet.microsoft.com. Through quick links to release notes, support policies, etc., developers can get a better understanding of what bits they installed.

Feedback is welcome.