[feature request] nb viewer buttons

[neuronflow]

we want NB viewer buttons, as we have them for panoptica, example here:
https://github.com/BrainLesion/panoptica?tab=readme-ov-file#semantic-segmentation-input

[MarcelRosier]

where do we want them? Shouldn't this be an issue on the specific repos rather than in the tutorials repo? @neuronflow