Add package readme to framework packages (#106097)

Author: ericstj

src/installer/pkg/sfx/Microsoft.NETCore.App/Directory.Build.props

@@ -6,6 +6,7 @@
     <SharedFrameworkName>$(MicrosoftNetCoreAppFrameworkName)</SharedFrameworkName>
     <IsShipping Condition="'$(PgoInstrument)' != ''">false</IsShipping>
     <SharedFrameworkFriendlyName>.NET Runtime</SharedFrameworkFriendlyName>
+    <EnableDefaultPackageReadmeFile>true</EnableDefaultPackageReadmeFile>
   </PropertyGroup>
 
   <!--
@@ -106,7 +107,7 @@
     <PlatformManifestFileEntry Include="libclrgc.dylib" IsNative="true" />
     <PlatformManifestFileEntry Include="clrgcexp.dll" IsNative="true" />
     <PlatformManifestFileEntry Include="libclrgcexp.so" IsNative="true" />
-    <PlatformManifestFileEntry Include="libclrgcexp.dylib" IsNative="true" />    
+    <PlatformManifestFileEntry Include="libclrgcexp.dylib" IsNative="true" />
     <PlatformManifestFileEntry Include="clretwrc.dll" IsNative="true" />
     <PlatformManifestFileEntry Include="clrjit.dll" IsNative="true" />
     <PlatformManifestFileEntry Condition="'$(PgoInstrument)' != ''" Include="pgort140.dll" IsNative="true" />

src/installer/pkg/sfx/Microsoft.NETCore.App/PACKAGE.md

@@ -0,0 +1,20 @@
+## About
+
+This package consists of the components that make up the Microsoft.NETCore.App framework.
+
+## How to Use
+
+Do not directly reference this package.  It's used by the .NET SDK when projects target .NET.
+
+## Additional Documentation
+
+<!-- Links to further documentation -->
+
+- [Conceptual documentation](https://learn.microsoft.com/en-us/dotnet/core/introduction)
+- [API documentation](https://learn.microsoft.com/en-us/dotnet/api)
+
+## Feedback & Contributing
+
+<!-- How to provide feedback on this package and contribute to it -->
+
+.NET is released as open source under the [MIT license](https://licenses.nuget.org/MIT). Bug reports and contributions are welcome at [the GitHub repository](https://github.com/dotnet/runtime).