Allow custom label for Start button

[datakurre]

For a continuing starter, clicking Start button again and again sounds confusing. On the other hand, changing button labels in fly is also confusing...

So, maybe not changes yet, but some discussion.

[bollwyvl]

If this was built into rjsf uiSchema, it would already be there, but for whatever reason, this is not supported.

If it was like a cassette recorder, there would be all of the buttons I remember reverently learning as a small child ⏪ ⏸⏺⏹▶️⏩.

The time-travel piece would be 😱 (see other reference about git) but let's not get ahead of ourselves.

So if this (and the jss styling) did exist, I'd imagine something like:

      "whitepaper-single": {
        "type": "notebook",
        "label": "Something",
        "description": "It does... something",
        "src": "something.ipynb",
        "tools": [
            {
                "command": {"id": "starters:cancel"},
                "title": "ABORT",
                "description": "stop the madness",
                "icon": "<svg><text>⏹</text></svg>",
                "style": {
                    "color": "orange"
                }
            },
            {
                "command": {"id": "starters:advance"},
                "title": "Make it so",
                "description": "do my bidding",
                "icon": "<svg><text>▶️</text></svg>",
                "style": {
                    "color": "blue"
                }
            }
        ]
      },

By making them commands, one could make some very interesting stuff indeed... and this is very close, already, to the specification of the JupyterLab toolbar, so it might make sense to use that instead of the existing custom button component (though they probably need to be bigger than default toolbar buttons).

[bollwyvl]

oh, and docs are up:
https://jupyterstarters.readthedocs.io