Cardano Updates

  I've defined a helper 'withTVarTracer' to get a tracer which puts logs in a TVar instead of outputting to stdout.

Seems like we have a fixed time limit for handshaking now

This uses again a hard-coded 'NewEpochState' instead of the
half-hard-coded LedgersEnv

This also writes contract instance ids to Wxxx.cid files

This is running the PAB in Simulation mode and can be communicated with
using HTTP

This is a follow-up of [constraints
grouping](https://github.com/input-output-hk/hydra-poc/wiki/Coding-Standards#constraints-grouping) approval.

  I've also done some re-alignment between 'withOuroborosNetwork' and 'withZeroMQNetwork' to take the tracer first.
  Also needed to parameterize the 'HydraMessage' log object with the network, since it was tailored to ZeroMQ so far.

Fix dead links in architectural document homepage

  We did so for the initiator side for the same reason: this tracer is very noisy
  and provides little useful information from the application standpoint. Other
  protocol-level tracers (such as the handshake tracer) provides more meaningful
  logs.

  Use permalink to ensure links always point to what they meant to point
  when written. As a drawback, the documentation may get outdated over
  time.