Make the CLI support "containers" of various kinds

[alilleybrinker]

Is your feature request related to a problem? Please describe.
Right now, the id and find commands handle recursive directory structures, but do not introspect on any files which can rightly be considered "containers." This can include:

• .zip files
• .tar files
• Docker images
• .jar files
• Many, many, many others

Ideally, we could do so, but there are some key questions:

• What would the UI be?
• How can we make sure we're consistent with other OmniBOR tools?

@dpp raised the second point specifically in today's OmniBOR Working Group meeting. We want to make sure we have a single way to do this across the tools and systems we produce, so that everything is cohesive.