Add json output

## What
Like Spin, it's better to output the results with JSON format.

## Why

Because JSON has more portability. Users can pass the `marco` results to `jq` to do some transformation, analytics, etc.

## Why not use Spin

Spin outputs the result with the logs included. 
And it does not support org-wide {application, pipeline} listing feature.

I would like to support this on `marco`.