feat: add fields Submitter / CoMaintainers to metadata-archives

This adds "Submitter" and "CoMaintainers" to the metadata archives

Submitter -> packages-meta-v1.json.gz & packages-meta-ext-v1.json.gz
CoMaintainers -> packages-meta-ext-v1.json.gz

Preparation to get #400 (closed) and #395 (closed) exposed via /rpc

Signed-off-by: moson-mo mo-son@mailbox.org