This PR removes the REPL panel and replaces it with a new sessions view
that gets displayed in its own pane.
The sessions view can be opened with the `repl: sessions` command (we
can adjust the name, as needed).
There was a rather in-depth refactoring needed to extricate the various
REPL functionality on the editor from the `RuntimePanel`.
<img width="1136" alt="Screenshot 2024-07-22 at 4 12 12 PM"
src="https://github.com/user-attachments/assets/ac0da351-778e-4200-b08c-39f9e77d78bf">
<img width="1136" alt="Screenshot 2024-07-22 at 4 12 17 PM"
src="https://github.com/user-attachments/assets/6ca53476-6ac4-4f8b-afc8-f7863f7065c7">
Release Notes:
- N/A
This PR factors a `ReplStore` out of the `RuntimePanel`.
Since we're planning to remove the `RuntimePanel` and replace it with an
ephemeral tab that can be opened, we need the kernel specifications and
sessions to have somewhere long-lived that they can reside in.
Release Notes:
- N/A