* NuGet packaging

* Add missing VS package references

* Fix scripts

* Add comment on Workspace.Desktop references with PrivateAssets

* Fix Microsoft.NETCore.Compilers package

* Fix up references

* Build fixes

* Correct OutputPath for package projects

* Use NuGetRepack to force exact versions in per-build packages

In the new SDK we no longer have a need for ProjectGuid. This change
will:

- Remove ProjectGuid from project files
- Remove Name + Project items from ProjectReference entries
- Change BuildBoss to enforce both of these items

Introduce a more flexible service to allow languages to plug into common comment/uncomment behavior.

This diagnostic analyzer checks the index values of all placeholders in a format
string. If a placeholder in the string is out of range, a warning message is displayed.

fixes bug #15856