* Clean up string resources, use Arcade resx generator

* CodeLens resources


* Use NET20 instead of NETFX20

The `$(RuntimeIdentifiers)` property was added some time ago to support
scenarios like self contained in our infrastructure. That is no longer
done during build and this property is no longer necessary. Further it's
causing us additional restore time to bring down runtimes we don't need.

* Remove RoslynProjectType

* Remove ToolsVersion, namespace from Project tags

* Remove updating of MSBuildAllProjects

* Update BuildBoss

* Delete DeployTooolsetCompiler

These issues should be fixed now. Enabling the assemblise again.

* Use Arcade testing targets

* Skip CodeStyle tests on Mono

* Include net472 in test target frameworks for Mono

* Remove incorrect file existence check.

* Update ADO integration test yaml

* Move xunit package references to Roslyn.Toolsets.Xunit.targets

* Remove dependency on Microsoft.NET.Test.Sdk

The C# syntax tests were missing a reference to xunit.runner.visualstudio
which prevented them from working in the Test Explorer in 15.8 Preview.
Rather than just adding a reference to this one test, I've added a reference
to the root test utilities project, that almsot every test references, and
deleted the explicit references in the test leaf projects. This should
hopefully be a more robust method of using the XUnit VS test adapter.

This primarily moves us to the 2.2.0 version of xunit. In order to make
that transition though a number of other changes needed to happen as
well:

1. Needed to move our desktop target to 4.6.1. This should've been
required some time ago but we were essentially depending on bugs in the
SDK / NuGet.
1. Remove the DeployCoreClrTestRuntime project. This entire idea
depended on having the xunit.console.netcore package. This has since
been deleted and doesn't work with the 2.0 SDK.
1. Remove the deploy compiler tools project. Can just use dotnet exec
now and that's much more efficient.
1. Resolve a new ambiguity with KeyValuePair. A helper of ours now
exists in netcoreapp2.0.

I fully expect a number of Jenkins legs to fail with this change: build
correctness, coreclr and ubuntu. But I want to validate our other legs
and am still trackind down answers needed to fix the others.

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

Move IVsSQM.cs to VS where it was being used as a linked file.

Migrated the remainder of our code base to use the new SDK via the
ConvertPackageRef tool.

https://github.com/jaredpar/ConvertPackageRef

This is an automated migration of our project files to the new SDK /
PackageReference.  It is done using the tool located here:

https://github.com/jaredpar/ConvertPackageRef

This project is no longer necessary.  It used to help us get TDD working fine in Visual Studio.  That's no lonegr needed with the recent build cleanup.  TDD still functions with this project removed.

The Compilers.sln solution is compiling again and tests which don't
require AppDomain support are running again.  There is a bit of work
that is needed for AppDomains that I want to separate out.  In
particular the separation to portable means we have to redo some of the
serialization code.