Add _Nx Note_ visualization

[axelboc]

Fix #1603

Nothing crazy, but there is a subtlety: the MIME type is stored in a dataset and not an attribute (:shrug:), which means that with our current architecture, we don't have access to it when looking for supported visualizations. We can only detect that the group has NX_class=NXnote, render NxNoteContainer, and only then fetch the values of the data and type datasets. So if the MIME type is not JSON, we get:

When ideally, it would be nicer to show the default fallback (without the NX Note tab):

I could refactor the visualization detection code so it allows fetching dataset values. The downside is that it will trigger the suspense fallback that wraps the whole Visualizer. I guess it's okay as long as we fetch only datasets that contain metadata and not actual data... Any thoughts @loichuder?

[axelboc]

/approve

[loichuder]

I could refactor the visualization detection code so it allows fetching dataset values. The downside is that it will trigger the suspense fallback that wraps the whole Visualizer. I guess it's okay as long as we fetch only datasets that contain metadata and not actual data... Any thoughts @loichuder?

I think it is fine as it is for several reasons:

• The logic is the same than other NeXus vis that also need to fetch values from other datasets
• The different error message when clicking on a NxNote gives an indication to the user that a richer visualization can be achieved by changing the MIME type in type
• I don't expect many NxNote usecases to pop up :smiling_face_with_tear: