Add Policy registry commands

[emcfarlane]

This PR adds the policy registry commands to the CLI. The following commands are added:

policy         Manage BSR policies
  commit       Manage a policy's commits
    add-label  Add labels to a commit
    info       Get commit information
    list       List policy commits
    resolve    Resolve commit from a reference
  create       Create a BSR policy
  delete       Delete a BSR policy
  info         Get a BSR policy
  label        Manage a policy's labels
    archive    Archive a policy label
    info       Show label information
    list       List policy labels
    unarchive  Unarchive a policy label
  settings     Manage a policy's settings
    update     Update BSR policy settings

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 1, 2025, 10:06 PM