wintypes: Partially implement RoResolveNamespace and add 'Windows.winmd'
The Visual Studio 2022 installer needs to be able to lookup a valid WinMD file for the 'Windows.Networking.Connectivity' namespace in order for the installation to start.
A normal Windows installation contains lots of individual '.winmd' files (e.g. 'Windows.Networking.winmd'), which we cannot redistribute. Fortunately, Microsoft provides an open-source project called 'windows-rs', which contains a combined 'Windows.winmd' file that is explicitly MIT-licensed: https://github.com/microsoft/windows-rs/blob/master/crates/libs/bindgen/default/Windows.winmd
Make RoResolveNamespace resolve anything starting with 'Windows' by just pointing to this giant file. A full implementation will require us to actually walk the 'WinMetadata' directory (if the caller provides a custom path) and parse the matched '.winmd' file. However, this implementation is good enough for Visual Studio 2022
To actually run the vs2022 installer, a patch for the SHELL_execute trailing-space bug https://bugs.winehq.org/show_bug.cgi?id=56940 is needed: !6079 (closed)