Hide all but 3 of our icons in the native notebook

[rchiodo]

For both stable and insiders hide all but 3.

The 3 are to be determined.

Others can be forced into the overflow menu.

[claudiaregio]

Top 3 to be used:

1. Restart kernel
2. Variable Explorer
3. Export As
   When kernel is in busy state, turn the restart kernel notebook toolbar icon into the STOP EXECUTION RED SQUARE ICON. When kernel is in idle state, turn back into the kernel restart icon.

Untrusted icon to be the only icon displayed in the toolbar until notebook is trusted.

*Change for both stable and insiders so experience is consistent for both

[rchiodo]

Not sure yet about the the icon/command changing.

This might work:

                {
                    "command": "jupyter.notebookeditor.restartkernel",
                    "title": "%jupyter.command.jupyter.restartkernel.title%",
                    "group": "navigation@3",
                    "when": "notebookViewType == 'jupyter-notebook' && !jupyter.isbusy"
                },
                {
                    "command": "jupyter.notebookeditor.interruptkernel",
                    "title": "%jupyter.command.jupyter.interruptkernel.title%",
                    "group": "navigation@3",
                    "when": "notebookViewType == 'jupyter-notebook' && jupyter.isbusy"
                },

I'd have to code it up to find out.

[IanMatthewHuff]

Validated.

Restart, Variable, Export As