Create a custom protocol for ddshow

[Kixiron]

In an effort to stay backwards compatible with timely's builtin logging streams, DDShow currently uses separate tcp streams for timely, differential and progress logging. However, with the introduction of ddshow-sink and the rkyv types we have the basis to make an entirely custom protocol that's significantly easier to use

Pros:

• Doesn't require up to three separate tcp streams to be specified by users
• Doesn't require the user to know the number of timely workers in the target program
• Could allow intermittent logging (currently the builtin timely loggers panic and crash the target program if either side disconnects)

Cons:

• Increases complexity some more
• Loses backcompat with timely stuff (only to an extent though, the current abomonated sink/streams could still be kept and be comparable with timely's stock stuff)

cc @ryzhyk