add feature to remux signed rtmp stream

[D4rkTT]

Bug: if main stream (RTMP) protected by signed key and user validating the sign argument on "prePlay" event then user won't able to remux because remux don't pass config args to trans session Fix: pass sign argument if available so user able to remux signed rtmp stream

[mattcwebster]

Please look into this one @illuspas I've noticed too that the fission streams don't have the session.publishPlayArgs with the sign argument so there's no way to auth fission paths.

[D4rkTT]

@mattcwebster this for trans muxer its different for fission i will edit it too to fix it