* Mark eng\docker\mono.sh executable

* Report error if docker build fails.

* Remove RuntimeIdentifier specification

* Arcade directory layout

* 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

* Use Arcade dotnet install scripts

* Update roslyn-tools build tasks to 1.0.0-beta3.18523.2

* DotNet version check, remove LocateDotNet.

Move Linux build logic to build\scripts\build.sh
Eliminate MicroBuild scripts

* 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

* Update .NET SDK to 2.1.300-rtm-008866

* Set TargetLatestRuntimePatch to false for ILAsm

* Kill build processes after boostrapping phase

* Fix SDK tests

Change our Unix builds to create the set of NuGet packages that are needed for
source build.

This is necessary to install pre-release .debs of the Mono runtime.