Remove lockbot message, re-engage lockbot
Remove lockbot message, re-engage lockbot

This removes the lockbot message so we don't get inundated with the backlog of closed issues being locked. It also adds a status:resolved-locked label which has description "Closed issues are locked after no recent activity. Please open a new issue for related discussion." to help users understand what the lock means.
jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab