[Poetry] reimplement `show` command

[Secrus]

See python-poetry/poetry#3827, python-poetry/poetry#1990, python-poetry/poetry#2134

show command should produce a report detached from CLI, so that it can be later displayed on CLI or rendered to JSON/CSV for other tools to analyze easily.

There is also an implementation of dict to CLI Tree inside the current state. This should be extracted to Cleo as a generic component (delegated to trag1c).