MINOR: quic-be: QUIC connection allocation adaptation (qc_new_conn())

MINOR: quic-be: QUIC connection allocation adaptation (qc_new_conn())

For haproxy QUIC servers (or QUIC clients), the peer is considered as validated.
This is a property which is more specific to QUIC servers (haproxy QUIC listeners).
No <odcid> is used for the QUIC client connection. It is used only on the QUIC server side.
The <token_odcid> is also not used on the QUIC client side. It must be embedded into
the transport parameters only on the QUIC server side.
The quic_conn is created before the socket allocation. So, the local address is
zeroed.
Initilize the transport parameter with qc_srv_params_init().
Stop hardcoding the <server> parameter passed value to qc_new_isecs() to correctly
initialize the Initial secrets.