This change removes the embedded http.Server struct from http3.Server.
It slightly changes some error behavior, in particular, it mandates
TLSConfig for methods that create QUIC listeners.
Before this change, only Addr, TLSConfig, Handler and MaxHeaderBytes
options were used from the http.Server. These are now defined directly
in http3.Server with an improved documentation.
* feat(http3): implement serving from quic.Listener
ServeListener method added to http3.Server allowing serving from an existing listener
ConfigureTLSConfig function added to http3 which should be used to create listeners meant for serving http3.
* docs(http3): add note about using ConfigureTLSConfig to ServeListener
* fix(http3): stop serving non-created listeners after Server.Close
* refactor(http3): return ErrServerClosed once server closes instead of context.Canceled
* feat(http3): close listeners from ServeListener as well
* fix(http3): fix logger not being setup during ServeListener
* test(http3): add unit tests for serving listeners
* test(http3): add tests for ConfigureTLSConfig
* test(http3): added server hotswapping integration test
* fix: race condition in listener tests
