Printing log messages

[coot]

• [ ] All Show instances, should be either derived or at least look similar.
• [ ] Provide a pretty printing type class) and instances for the types which do pretty printing in their Show instances. If we decide to use Condense, we need to make our pretty printers condensed & human readable, not just human readable.
• [ ] cardano-node: Show should be used in the text mode, pretty printing should be used in json mode. If we decide to use Condensed we should use it consistently with the consensus team.

[dcoutts]

I think it should be broader and we should have a deliberate type class that we use for rendering log items into human readable messages (as a default that can be used in the node top level), and use that type class across the network and consensus packages. The Condense class was not intended for that purpose.