Distribute MSBuild as stand alone nuget package

In order to make builds reproducible it would be good to store all tools used during build in the source control system. E.g. MSBuild. That will make builds independent from what is installed on the build agents. That will simplify upgrading msbuild as well. Just install new package and commit - you're done for all agents. Ideally compiler should also be distributed as stand alone nuget packages.