feat: add method for `janus-cli package metadata` ; generate updates to package.json for all plugins listed in plugins/plugin-metadata.json#1627

nickboldt wants to merge 19 commits intomainjanus-idp/backstage-plugins:mainfrom

RHIDP-1502-add-plugin-metadatajanus-idp/backstage-plugins:RHIDP-1502-add-plugin-metadataCopy head branch name to clipboard