* Invert the dependency between connection adapters and Frame
- Removed PrepareRequest from IAdaptedConnection and instead added
a feature collection to the ConnectionAdapterContext. This allows features to be set
once by the adapter instead of per request. It's the Frame's job to copy features
from the connection level feature collection into the per request feature collection.
- Set the scheme to "https" based on the presence of ITlsConnectionFeature.
- Always set ITlsConnection feature if the HttpsAdaptedConnection doesn't throw during
the handshake
Add an internal API to ListenOptions to determine if an endpoint is configured to use HTTPS. This is a temporary as the design of connection adapters and configuration will churn before release.
- Put everything in the libuv transport package under `Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.*` namespaces.
- Move stuff in Transport.Libuv/Internal/Http and Transport.Libuv/Internal/Infrastructure to Transport.Libuv/Internal (keep the Networking directory for the libuv wrappers).
- Add `Libuv` prefix to most libuv internal classes.
- Rename `KestrelEngine` to `LibuvTransport`.
- Rename `SocketOutputConsumer` to `LibuvOutputConsumer`.
- Rename `SocketOutputProducer` to `OutputProducer`.
- Fix namespaces in `Microsoft.AspNetCore.Server.Kestrel.Core.`