Connection states code cleanup.

Connection states code cleanup.

 + ngx_quic_init_ssl_methods() is no longer there, we setup methods on SSL
   connection directly.

 + the handshake_handler is actually a generic quic input handler

 + updated c->log->action and debug to reflect changes and be more informative

 + c->quic is always set in ngx_quic_input()

 + the quic connection state is set by the results of SSL_do_handshake();