web console: display index_parallel progress

Native batch ingestion exposes progress stats for its subtasks (number of succeeded/running/total/etc tasks) on the `http://{PEON_IP}:{PEON_PORT}/druid/worker/v1/chat/{SUPERVISOR_TASK_ID}/progress` endpoint.

It would be great if this were visible somewhere while examining an index_parallel task in the web console, either somewhere in the popup revealed by the magnifying glass icon, or even in a column in the task list as a progress bar.

It might be a good idea to proxy this task through another server (overlord?) because peon hostnames might not be resolvable from a user's browser.

Start with the web console view for an index_parallel task and the progress endpoint at /druid/worker/v1/chat/{SUPERVISOR_TASK_ID}/progress. Determine whether the statistics belong in the magnifying-glass popup or task list, and ensure the progress data can be accessed when peon hostnames are not resolvable from the browser.

Written by the indexing model from the issue text.