Put core middleware "together"

[davidfowl]

This still needs some design work but these middleware a core to pretty much every application:

• Map
• Run
• UseMiddleware(middlewareType)
• UseServices

There could be a meta package that brings these in.

[Tratcher]

Use(middleareType, args) and UseContainer are currently in the Hosting repo in the Microsoft.AspNet.RequestContainer assembly.

Run is currently implemented directly on the IBuilder interface.

Recommendation:

• Rename this assembly to Microsoft.AspNet.Pipeline and move it to the HttpAbstractions repo.
• Add Map to this assembly
• Move Run to this assembly

[Tratcher]

Updated proposal:

• Implement Map and Run in HttpAbstractions
• UseMiddleware and UseServices have DI dependencies, so leave them where they are or move them to the new BuilderComposition repo.

[Tratcher]

#20 Complete for Map, Run, and Use.

Now what do we do with UseMiddleware and UseServices?

[glennc]

Leaving these where they are for now, there will be reviews later that will revisit them.