Add a test quicserver utility

Add a test quicserver utility

This QUIC server utility is intended for test purposes only and is expected
to be replaced in a future version of OpenSSL by s_server. At that point
it will be removed.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21204)