Add pane-closing functionality

[JosephTLyons]

Check for existing issues

• [X] Completed

Is your feature request related to a problem?

We currently have

• Close active item (close this file)
• Close inactive items (close all files but this file)

These are operations that are performed on files. It would be great if we had the same functionality for panes

• Close active pane (close this pane)
• Close inactive panes (close all panes but this pane)

If we were to implement this, we might want to change the names of the first 2 commands to be more specific to files / tabs.

Something to consider is, how does this look on the UI? Is this something we surface to the user on the UI, or do we omit it to keep the UI from being too noisy, and only support triggering them from commands?

Describe the solution you'd like

Implement:

• Close active pane (close this pane)
• Close inactive panes (close all panes but this pane)

If applicable, add mockups / screenshots to help present your vision of the feature

No response

[failable]

It would also be helpful to have commands like "Close other pane" that close the sibling pane without moving to that pane before closing.

[ZelCloud]

Close Active File should also have an option to Close Active File without Saving