Merge dotnet/Installer src and test folder histories (#40084)

Author: MiYanni

src/Microsoft.Dotnet.Sdk.Internal/Microsoft.Dotnet.Sdk.Internal.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <!-- This is an empty project that exists to be published by DARC and trigger
+  dependency uptake for this repo. -->
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <IsPackable Condition="$(PublishInternalAsset) == true">true</IsPackable>
+    <IsShipping>false</IsShipping>
+  </PropertyGroup>
+
+</Project>

src/SourceBuild/README.md

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+# Source-Build
+
+This directory contains the .NET source build infrastructure.
+
+_content_ - source build infrastructure mirrored to [dotnet/dotnet](https://github.com/dotnet/dotnet)
+    [VMR](https://github.com/dotnet/arcade/blob/main/Documentation/UnifiedBuild/VMR-Design-And-Operation.md).
+
+_patches_ - repo patches needed for .NET source build. Typically these are ephemeral to workaround integration
+    issues. For more information, see the [Patch Guidelines](https://github.com/dotnet/source-build/blob/main/Documentation/patching-guidelines.md).
+
+For more information, see [dotnet/source-build](https://github.com/dotnet/source-build).
+
+## Local development workflow
+
+When making changes to the source build infrastructure, devs would typically make and test the
+changes in a local clone of [dotnet/dotnet](https://github.com/dotnet/dotnet). Once complete
+you would copy the changed files here and make a PR. To validate the end to end experience, you
+can synchronize the VMR with any changes made here by running [eng/vmr-sync.sh](https://github.com/dotnet/installer/blob/main/eng/vmr-sync.sh).

src/SourceBuild/content/.config/1espt/PipelineAutobaseliningConfig.yml

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+## DO NOT MODIFY THIS FILE MANUALLY. This is part of auto-baselining from 1ES Pipeline Templates. Go to [https://aka.ms/1espt-autobaselining] for more details.
+
+pipelines:
+  1330:
+    retail:
+      source:
+        credscan:
+          lastModifiedDate: 2024-03-25
+        eslint:
+          lastModifiedDate: 2024-03-25
+        psscriptanalyzer:
+          lastModifiedDate: 2024-03-25
+        armory:
+          lastModifiedDate: 2024-03-25
+      binary:
+        credscan:
+          lastModifiedDate: 2024-03-25
+        binskim:
+          lastModifiedDate: 2024-03-25
+        spotbugs:
+          lastModifiedDate: 2024-03-25