feat: rename skills with openhands- prefix, create unified plugins/openhands bundler https://github.com/OpenHands/extensions/pull/174 @quick-window-91705 @elegant-branch-54423 which appreciate reviews here since it bundles in automation & joe's "openhands-cloud" skill PR

heads up I just merged some new changes in https://github.com/OpenHands/extensions/pull/191