fix: logs should go to stdout not stderr

[alexander-camuto]

env_logger by default targets stderr not stdout which causes annoyances like those highlighted in #148; hindering the ability for external packages / languages to leverage the cli as a subprocess. Here we remedy this issue by removing colog, and explicitly setting the logging target to STDOUT.

Whilst we're at it this PR also introduces a number of cosmetic improvements that were desperately needed.

• logging timestamps
• logging metadata (the submodule it was called from).
• pretty printing of JSON of cli command.

Resolves #148