Upgrade SMO to 150 preview (#701)

* Switch to the unified SMO NuGet so all binaries are strong named and signed.

* use one AssemblyLoader instance for all loads

* Revert "use one AssemblyLoader instance for all loads"

This reverts commit 48c59ffd5c57152de281c87acdbcad7ddf7ab760.

* Stop creating multiple AssemblyLoadContext objects during composition, per https://github.com/dotnet/coreclr/issues/19632

* restore high entropyva property

* Improve the comment

* Update SMO to 150 and fix scripting for objects with a single quote in their name.

* restore newtonsoft reference

src/Microsoft.SqlTools.ResourceProvider/Microsoft.SqlTools.ResourceProvider.csproj

@@ -1,4 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="../../Common.props" />
   <PropertyGroup>
     <TargetFramework>netcoreapp2.1</TargetFramework>
     <PackageId>SqlToolsResourceProviderService</PackageId>
@@ -11,7 +12,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PreserveCompilationContext>true</PreserveCompilationContext>
     <DebugType>portable</DebugType>
-	  <EnableDefaultEmbeddedResourceItems>false</EnableDefaultEmbeddedResourceItems>
+	<EnableDefaultEmbeddedResourceItems>false</EnableDefaultEmbeddedResourceItems>
     <RuntimeIdentifiers>win7-x64;win7-x86;ubuntu.14.04-x64;ubuntu.16.04-x64;centos.7-x64;rhel.7.2-x64;debian.8-x64;fedora.23-x64;opensuse.13.2-x64;osx.10.11-x64;linux-x64</RuntimeIdentifiers>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">