feat: Add mgmt-api-oas package

[smwest3]

Description

This PR adds a new @a0-mgmt-api/oas package to docs-v2 to fulfill an internal task. It also updates the artifact generation script to include the new management api spec.

Checklist

• I've read and followed CONTRIBUTING.md.
• I've tested the site build for this change locally.
• I've made appropriate docs updates for any code or config changes.
• I've coordinated with the Product Docs and/or Docs Management team about non-trivial changes.

[nlucero]

Question: Should we, as part of this PR, also update the artifact generation script to include this new OAS to process? (Basically uncomment and update the entry for Management API in here).