Command-line argument to enable pretty-print OSCAL-CLI output

[Rene2mt]

User Story:

As an OSCAL content developer, I want OSCAL-CLI to provide a command-line argument to ensure generated XML, JSON and YAML output (e.g., resolved profile catalogs) are "pretty-print" formatted so it is more readable and doesn't generate large amounts of content differences when using comparison utilities.

Goals:

As an example, currently, a generated resolved profile catalog us unformatted and looks like this:

An external utility must be used to format the output so it looks like this:

FedRAMP is considering using the OSCAL-CLI in its CI/CD pipeline to generate certain OSCAL content (e.g., resolved profile catalogs, JSON and YAML versions of OSCAL documents). Having a built-in "pretty-print" capability will eliminate additional formatting step with an external utilities when generating OSCAL content that needs to be readable.

Dependencies:

TBD

Acceptance Criteria

• All website and readme documentation affected by the changes in this issue have been updated.
• A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.
• The CI-CD build process runs without any reported errors on the PR. This can be confirmed by reviewing that all checks have passed in the PR.