This moves source code that used to be in aspnet/Common. It was only used here, so this simplifies the process of working with these internal-only APIs.
cref https://github.com/aspnet/Common/pull/386
* Renames from API review
- Rename Microsoft.AspNetCore.Protocols.Abstractions to Microsoft.AspNetCore.Connections.Abstractions.
- Renamed IConnectionHandler to IConnectionDispatcher (and related properties and types)
- Added ConnectionHandler and UseConnectionHandler extension method to Connections.Abstractions.
- Use ActivatorUtilties to create the ConnectionHandler
PackageLineup is a way to manage PackageReference versions across large projects. It removes the version information from the repository and instead pulls the information from an external "lineup" file.