Convert this package into a pure metapackage, so that `UseSerilogRequestLogging()` can be made available without any other dependencies

https://github.com/serilog/serilog-aspnetcore/blob/76f4a513e0538418b829ff4ef266444351b726fa/src/Serilog.AspNetCore/Serilog.AspNetCore.csproj#L31

There is no code in the project that depends on the Serilog.Sinks.File package.

This causes the resulting Serilog.AspNetCore NuGet package to carry along an unnecessary dependency.

[nblumhardt]

I’m not keen on dropping the dependencies here, not least because of the downstream breakage, but also because this creates one more barrier to adopting Serilog: the default .NET web SDK includes the console logger provider for MEL, there’s no extra step to install it; the default .NET web SDK enables JSON config support … etc. etc.

Apart from the logging middleware in this package, everything else is already in fine-grained packages. If we extract the logging middleware to its own package, referenced from this one, then it’s easy to just install Hosting, Configuration, the middleware package, and whatever other sinks you require. Let’s push this one forward 😃

[GraemeF]

This is starting to cause problems - the unnecessary dependencies are becoming outdated which can lead to version downgrade errors when building (especially when targeting linux, it seems), and the workaround is to add direct dependencies to the later versions of these implicitly-included packages from our projects. Feels very wrong, as our projects don’t use these packages at all! 😄