Add missing registry keys for Microsoft.AspNetCore.App

[joeloff]

Description

During .NET Core 3.0, the SDK, Runtime and Desktop Runtime moved to using a single set of registry keys for Windows based installers to simplify detection. ASP.NET already had keys, but they were located in a completely different location in the registry.

App Services rapid update is looking at ways to simplify their detection logic and the registry keys are a feasible solution, but the ASP.NET keys are missing.

The old keys should be retained because removing them can break anyone relying on them This is just a request to add the central keys under HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\dotnet\Setup\InstalledVersions\<platform>\sharedfx. Note that these keys always go to the 32-bit registry view regardless of the MSI architecture.

Sample implementation

SDK implementation: https://github.com/dotnet/installer/blob/c949c4571bf2c334c30d2894f3de87552395c94b/src/redist/packaging/windows/registrykeys.wxs#L5C7-L9C19

Runtime/Desktop:
https://github.com/dotnet/arcade/blob/d54f6057363b8b249be56dcf8b91aa847f97a904/src/Microsoft.DotNet.Build.Tasks.Installers/build/wix/product/registrykeys.wxs#L8C7-L20C19

Backport

The changes should be backported to both 8.0 and 6.0 as those are LTS releases that will impact App Services.