Collapse managedFields by default in YAML

Various resources have a large `metadata.mangedFields` stanza that isn't important for users. We should see if we can collapse that section by default in the YAML editor.

I didn't see an obvious API in Monaco editor for doing this, but I could have missed it. We can reach out to the dev tools team who own the YAML language server to see if it's possible.

cc amobrem eparis@redhat.com