Move to MSTest and allow multi-targetting test runs

Previous all of the tmp files were create in the Samples directory. When
running tests against multiple runtimes this caused problems. Now the
tmp files are written to a subdirectory with the Environment.Version.
This isn't a great fix, but it is a workaround for now.

Author: decriptor

.editorconfig

@@ -50,6 +50,8 @@ dotnet_style_explicit_tuple_names = true:suggestion
 
 # CSharp code style settings:
 [*.cs]
+indent_style = tab
+indent_size = 4
 
 # spaces before parens
 csharp_space_between_method_declaration_name_and_open_parenthesis = true

Directory.Packages.props

@@ -1,15 +1,9 @@
 <Project>
-  <PropertyGroup>
-    <!-- Enable central package management, https://learn.microsoft.com/en-us/nuget/consume-packages/Central-Package-Management -->
-    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
-  </PropertyGroup>
-  <ItemGroup>
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.0" />
-    <PackageVersion Include="NUnit" Version="4.3.2" />
-    <PackageVersion Include="NUnit3TestAdapter" Version="5.0.0" />
-    <!-- This generates a TON of warnings (13k+ warnings) -->
-    <!--<PackageVersion Include="NUnit.Analyzers" Version="3.3.0" />-->
-    <PackageVersion Include="coverlet.collector" Version="6.0.4" />
-    <PackageVersion Include="SixLabors.ImageSharp" Version="2.1.10" />
-  </ItemGroup>
+	<PropertyGroup>
+		<ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+	</PropertyGroup>
+	<ItemGroup>
+		<PackageVersion Include="MSTest" Version="3.9.1" />
+		<PackageVersion Include="SixLabors.ImageSharp" Version="2.1.10" />
+	</ItemGroup>
 </Project>