Provide feedback that Jupyternaut is working

[JasonWeill]

Problem

When I submit a question to Jupyternaut in the chat UI, I don't get any visual feedback that Jupyternaut is thinking/working/typing/etc. This might lead a user to submit a second question, leading to further system load and expense.

Proposed Solution

Provide visual feedback that Jupyternaut is working. Potentially, have a detail view, with a list of all questions (including long-running ops like /generate commands) that Jupyternaut is working on.