[Policy Assistant] Standardized output format

[MrHohn]

The current output format of Policy Assistant is pretty focus on tables and human readability.

While it's very handy as its current form to use as a development/inspection tool, I'm wondering whether we will be considering further iterate on the output. For instance, if we can standardize the output format (e.g. JSON with well-defined fields), it will enable downstream clients to consume the output from Policy Assistant programmatically, which can lead to expanded use cases.