* unify servers; use tokio::TcpListener

* add API to build server from tcp socket

* build_from_tcp nit: not async

* fix nits

* change `build_from_tcp` force users configure hyper

The hyper settings might contradict to settings on the provided
socket, force users of this API to configure that avoid confusion and
unexpected settings.

* Update http-server/src/server.rs

* fix doc links

* add separate APIs `build_from_tcp` and `build_from_hyper`

* fix clippy

* remove dead code

* fix build

* fix nit in example code