Make F# installation inside VS folder version agnostic

[T-Gro]

Currently, the installation of F# specific bits inside Visual Studio are within a version-specific folder.
That folder name is configured in this repo, and has to be maintained. If that is not done, build launched from VS failed.
\Microsoft\VisualStudio\v17\FSharp\

The request is to make the installation version agnostic.

This has to be done with care due to projects using the legacy, non-SDK, project system.
There are many project files following this pattern:
https://github.com/MSRCCS/Prajna/blob/b982ed83bdd6e4fafcb6d5b8c75c69a2ffff7a9f/src/ULib/ULib.fsproj#L74

      <PropertyGroup>
        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>

A possible solution might include a version agnostic folder PLUS shortcuts that would meet the needs of legacy projects.