Stop referencing Docker Hub repos in GitHub readmes and documentation

[MichaelSimons]

In the past, the Docker Hub repo readmes were preferred because of the nicely formatted tags table. Due to size constraints these were removed. Because of that, it no longer makes sense to direct readers of the GitHub readmes and documentation to the Docker Hub readmes. Instead, the links should be updated to reference the appropriate GitHub readmes.

This is related to #5872 (comment)

[lbussell]

[Triage] This was fixed for dotnet-docker in #5921

@MichaelSimons Please file a follow-up issue to fix this in the microsoft/dotnet-framework-docker repo as well.

[lbussell]

[Triage] There are actually remaining references to DockerHub in the templated repo-specific readmes. For example:

dotnet-docker/README.aspnet.md

Lines 59 to 66 in 98c9450

	* [dotnet](https://hub.docker.com/r/microsoft/dotnet/): .NET
	* [dotnet/sdk](https://hub.docker.com/r/microsoft/dotnet-sdk/): .NET SDK
	* [dotnet/runtime](https://hub.docker.com/r/microsoft/dotnet-runtime/): .NET Runtime
	* [dotnet/runtime-deps](https://hub.docker.com/r/microsoft/dotnet-runtime-deps/): .NET Runtime Dependencies
	* [dotnet/monitor](https://hub.docker.com/r/microsoft/dotnet-monitor/): .NET Monitor Tool
	* [dotnet/aspire-dashboard](https://hub.docker.com/r/microsoft/dotnet-aspire-dashboard/): .NET Aspire Dashboard
	* [dotnet/samples](https://hub.docker.com/r/microsoft/dotnet-samples/): .NET Samples
	* [dotnet/nightly/aspnet](https://hub.docker.com/r/microsoft/dotnet-nightly-aspnet/): ASP.NET Core Runtime (Preview)

These should be fixed in a follow-up PR.