web client: add a CLI shim on top of the Python API

We already have a web client CLI for authentication, but not for querying information about archive objects. It can be something as simple as spitting to stdout formatted JSON output. And it will still provide value on top of just using curl (e.g., it will take care of pagination transparently, possibly use auth properly in the future, etc.).

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Migrated from T2671 (view on Phabricator)