mpegts: ensure PMT PID is stored and that on update service restarts
mpegts: don't pass unecessary stream specific PIDs for other streams

This mostly affected the PMTs which were all passed to any service, rather
than just the specific one for the relevant service.
muxer pass: some re-org, UI fixup and general tidying of PMT/PAT rewrite

I've made the PAT/PMT rewriting indepedently configured, currently I think
the multi-packet PMT is a limitation we need to look into.