bpo-41744: Package python.props with correct name in NuGet package (GH-22154)

NuGet automatically includes .props file from the build directory in the
target using the package, but only if the .props file has the correct
name: it must be $(id).props

Rename python.props correspondingly in all the nuspec variants. Also
keep python.props as it were for backward compatibility.
(cherry picked from commit 7c11a9acca)

Co-authored-by: Václav Slavík <vaclav@slavik.io>

Tools/nuget/python.nuspec

@@ -13,6 +13,6 @@
   </metadata>
   <files>
     <file src="**\*" exclude="python.props" target="tools" />
-    <file src="python.props" target="build\native" />
+    <file src="python.props" target="build\native\python.props" />
   </files>
 </package>