Investigate custom dashboard results

Following discussion in https://github.com/InsightSoftwareConsortium/itk-dreg/pull/2/files#r1355064085, it would be interesting to investigate how/whether we can add custom widgets/visuals to the Dask distributed dashboard to understand how well registration and reduction are working.

In theory it could be possible to visualize intermediate results in 3D with `itkwidgets` or similar. We could consider whether 2D/3D visuals would be most effective at the block-registration stage (many subimages), at the results reduction stage (one large result image), or both.

Related reading:

https://docs.dask.org/en/latest/dashboard.html
https://github.com/dask/distributed/issues/3503
https://github.com/InsightSoftwareConsortium/itk-dreg/pull/2/files#r1355064085

cc @thewtex