Cardano Updates

This will make it easier to transition to `contra-tracer-0.2` which
requires to replace `Tracer` with `Tracer . emit`.  Also removed usage
of `showTracing` which is not part of `contra-tracer-0.2`

This will make it easier to transition to `contra-tracer-0.2` which
requires to replace `Tracer` with `Tracer . emit`.  Also removed usage
of `showTracing` which is not part of `contra-tracer-0.2`

Using `contra-tracer < 0.2` forces cabal to select CHaP version of
`contra-tracer-0.1.0.2`.  We are not compatible with
`contra-tracer-0.{1,2}` from Hackage.

Add {To,From}JSON instances for TxSubmissionLogicVersion

Parametrise `Ouroboros.Network.Socket` API with monad `m`.  This patch
allows us to have a cleaner integration of ouroboros-network in
`dmq-node`, where we need to connect to the node, but we don't want to
be forced to use `IO` monad too early or pass callbacks around.

`label`s are easier to read, since `QuickCheck` will list each group in
a separate list.  This is important for the sim-net tests where we have
multiple nodes.  With a label we will get the output grouped by node,
since every node returns a labelled `Property`.

The tests-lib should only exposed generic traces which can be combined
as needed.   `debugTracerG` is removed, we only expose:

* debugTracer - a tracer to `stderr`
* dynamicTracer - a tracer using `traceM` (IOSim only)
* sayTracer - a tracer via `say` (IO & IOSim)

`debugTracerG` is removed.  It was only used in testnet simulation,
where now instead we use `dynamicTracer` and `sayTracer`.

Mini-protocol job handler should not throw synchronous exceptions.  If
it does, the job result won't be written to completion var and mux
monitoring loop won't be notified.

The `BlockedOnCompletionVar` exception was added only as a safety
measure that the `putMVar` should never block.  However, it's only safe
to do it in the `jobAction`.  We instead use `tryPutMVar` in the
`jobHandler` as a better alternative.