Record / Replay mode needs a UI

[msutkowski]

Assuming the infra work in #7 is merged, we need to come up with an idea for the UI for it. Some thoughts are:

General goals:

1. Provide ability to review requests/responses in a familiar format (like the network pane in chrome devtools)
2. Allow a user to select one, many, or all TrackedRequests to save a HAR file or output generated handler code directly.
   • Note: MSW itself is most likely going to recommend using HAR files, but in some cases users may want to have handler code that can be consumed directly.

UI Ideas

1. We could add a Drawer style component, or some other type of full screen overlay that allowed a user to see all of the TrackedRequests
2. Instead of a drawer, we could introduce a 'sub panel' that is re-sizable that attached to the bottom (assuming toolbar is at the top), that showed a stream of the requests
3. Per the above, a 'Live mode'! 🎉

Very much open to feedback here!