Debug cleanup.

Debug cleanup.

 + all dumps are moved under one of the following macros (undefined by default):
    NGX_QUIC_DEBUG_PACKETS
    NGX_QUIC_DEBUG_FRAMES
    NGX_QUIC_DEBUG_FRAMES_ALLOC
    NGX_QUIC_DEBUG_CRYPTO

 + all QUIC debug messages got "quic " prefix

 + all input frames are reported as "quic frame in FOO_FRAME bar:1 baz:2"

 + all outgoing frames re reported as "quic frame out foo bar baz"

 + all stream operations are prefixed with id, like: "quic stream id 0x33 recv"

 + all transport parameters are prefixed with "quic tp"
   (hex dump is moved to caller, to avoid using ngx_cycle->log)

 + packet flags and some other debug messages are updated to
   include packet type