* Make Sockets the default transport
* Create separate Libuv and Sockets functional test projects
* Fix functional tests that fail with Sockets
* Moved OneToTenThreads test to Kestrel.Transport.Libuv.Tests
* Fix systemd activation tests to use libuv transport
* Dispose Sockets PipeFactory
* Improve Socket's server-side abort handling
* Add explicit rebinding test
* Added initial connection middleware pipeline
- Implemented IConnectionBuilder on ListenOptions. Kept IConnectionAdapter for now.
- Delay the configure callback for ListenOptions until the server has started.
- Added ConnectionLimitMiddleware and HttpConnectionMiddleware
- Expose ConnectionAborted and ConnectionClosed on ConnectionContext and
IConnectionTransportFeature
- Updated the tests
- Removed IConnectionApplicationFeature
- Moved Application to IConnectionTransportFeature