Support more viewer options in the ImJoy API

Would be nice to be able to pass viewer options when creating the viewer window including cmap, ui_collapsed, rotate, axes, mode etc. Just like the options accepted by the view function in the itkwidgets,

This can be passed as config:

const viewer = await api.createWindow({
  src: "https://kitware.github.io/itk-vtk-viewer/app/",
  config: {...viewer options...},
  data: { image: imageArray }
})

For updating the options later, perhaps would be also nice to have setConfig (and getConfig).

[thewtex]

👍 👍 support for this in #343

[oeway]

The pause for the viewer initialization appears to be in the data transfer. Is there a way that the imjoy-rpc codec system could be used to pass progress callbacks? We could then not only show a spinner but also the transfer progress for the default network transfer. Also, a custom codec (zarr-blosc) could emit progress information based on the number of transferred, decompressed, chunks?

For custom codec, we can directly emit progress in the encoder/decoder function. For the transfer progress, typically we just send the data through a certain transport layer (e.g. jupyter or socketio) without knowing the progress. However, I think we can easily support that by changing the way we send data, for example, say we want to send a numpy array to another peer, instead of directly sending the data, we can send a getChunk function together with its total length, then the other peer can fetch data chunk by chunk. We can then easily add a callback function in the getChunk function to report the progress. This can be done by a custom codec, or we can do it directly by default, we will need to think about the api though. Any idea on how the api should look like?