Simplify dotnet/samples tags tables by un-documenting arch specific tags

[lbussell]

With #5057 and #5850, the samples tags tables have gotten very busy. It could be intimidating for users trying to choose between sample images to try, which is the opposite of what we want.

We should consider un-documenting some of the samples tags to simplify the table.

Example before:

Tags	Dockerfile	OS Version
dotnetapp-9.0-alpine-amd64, dotnetapp-9.0	Dockerfile	Alpine
dotnetapp-chiseled-9.0-amd64, dotnetapp-chiseled-9.0	Dockerfile	Ubuntu
aspnetapp-9.0-alpine-amd64, aspnetapp-9.0	Dockerfile	Alpine
aspnetapp-chiseled-9.0-amd64, aspnetapp-chiseled-9.0	Dockerfile	Ubuntu
dotnetapp-8.0-alpine-amd64, dotnetapp-alpine-amd64, dotnetapp-8.0, dotnetapp, latest	Dockerfile	Alpine
dotnetapp-chiseled-8.0-amd64, dotnetapp-chiseled-amd64, dotnetapp-chiseled-8.0, dotnetapp-chiseled	Dockerfile	Ubuntu
aspnetapp-8.0-alpine-amd64, aspnetapp-alpine-amd64, aspnetapp-8.0, aspnetapp	Dockerfile	Alpine
aspnetapp-chiseled-8.0-amd64, aspnetapp-chiseled-amd64, aspnetapp-chiseled-8.0, aspnetapp-chiseled	Dockerfile	Ubuntu

Example after un-documenting arch-specific samples tags:

Tags	Dockerfile	OS Version
dotnetapp-9.0	Dockerfile	Alpine
dotnetapp-chiseled-9.0	Dockerfile	Ubuntu
aspnetapp-9.0	Dockerfile	Alpine
aspnetapp-chiseled-9.0	Dockerfile	Ubuntu
dotnetapp-8.0, dotnetapp, latest	Dockerfile	Alpine
dotnetapp-chiseled-8.0, dotnetapp-chiseled	Dockerfile	Ubuntu
aspnetapp-8.0, aspnetapp	Dockerfile	Alpine
aspnetapp-chiseled-8.0, aspnetapp-chiseled	Dockerfile	Ubuntu