Discovery: print out discovered devices details

[marcelocf]

Story

As a developer I want to be able to see what devices I can discover in my network to guide me through the design and implementation phases.

Details

This is done once I have a featured discovery process that is meant to run once and quit, but that can send and receive multiple discovery request through echonet lite.

This is a requirement because once querying for discovery we first receive Panel responses; only when drilling down further in the instances we are able to fetch more information of what is available. We are interested in the properties we can set for non panel things.

[marcelocf]

Creating this as first actual workable item based on my experience working on this before. Reason being is that once we have this information we can start playing with the other aspects of the design.

In particular, this will be an async implementation based on tokio; as such we will have different tasks running doing multiple i/o operations sending messages to each other. This adds some constraints on the data types we can use.

Therefore, creating this as the first task we essentially create a framework to experiment with that part of the design having usable echonet-lite-rs structs at our disposal.

Last time I had to do some ugly hacks to make it work... and it naturally resulted in a pretty bad code.