Re-arrange multiple cells in edit view

[akshayka]

Description

The ability to move multiple cells in the editor at a time.

Suggested solution

Select multiple cells via box selection (mouse click and drag), then drag to move the cells. Selected cells could also be moved with the usual keyboard shortcuts.

Alternative

• Similar functionality, but in the minimap.
• If Feature request: Collapsible markdown headings #1085 is implemented, a drag handle for sections demarcated by markdown headers

Additional context

https://discord.com/channels/1059888774789730424/1059888774789730427/1230175318220865636

[mscolnick]

If someone does pick this up, using one of the helper panels (maybe the Dependency Viewer Panel / mini-map) instead of the main view may easier to rearrange the cells.