TUN-10563: introduce QUICConnection interface

The bump of the QUIC library introduces a cyclic dependency between the connection and quic modules hence it is necessary to break this coupling.

Right now, the connection module depends on the quic module for the datagram v2/v3 and to which a QUIC connection (currently an interface) is passed.

As it is there is no issue however, under the hood, interface is a wrapper around an UDP connection and a QUIC connection meaning this type must be exposed to the quic module since the QUIC Connection will no longer be a interface but a struct.

Given the above, these changes introduce an interface, QUICConnection, with the surface used today in cloudflared and a struct, ConnWithCloser, that implements said interface within the quic module.

Closes TUN-10563