Improve the invalidation logs of Zinc

[jvican]

The current invalidation logs for Zinc are pretty ugly and could be formatted to be easier to understand.

Why is this an important issue? Working on the infrastructure around logging is important so that sbt and other build tools can diagnose issues with it in the most effective, straightforward way. We're not enabling this use case as much as we can, so far.

The goal of this ticket is to make them easier to read: whether that is vertical formatting, colors or better messages doesn't matter and it's up to the contributor that takes this up to decide.

The best way to see the current state is to run scripted, disabling buffer log (in the build sbt), and then choosing a random scripted test and making sure that there is an incOptions.properties file in the root with:

apiDebug = true
relationsDebug = true

A test that already has this information is value-class-underlying.

If you want to see the logs produced by Zinc within sbt, you can do logLevel in aConcreteProject := Level.Debug where aConcreteProject is the place you want to test it on. That can be executed with set in the shell too, so that you don't have to reload the build.