Visualization of distributed data

[SimonHeybrock]

Ultimately we will need to visualize data that is not available on the front end or a single MPI rank of the back end. Examples are (1) an instrument view including current rates on detectors or (2) an MDWorkspace.

Investigate and test potential solutions. Options are:

• Something written from scratch. For example, we could see what it would take to integrate Mantid's instrument view (see also https://github.com/mantidproject/mantid/issues/14890, which is basically a pre-requisite for this).
• Integrate with ParaView's parallel and remote rendering, i.e., feed data from the Mantid reduction directly into something like pvserver.

[SimonHeybrock]

The simplest thing we could do is something that mimics a basic instrument view:

1. Create a new transition that integrates each histogram, to get a per-pixel intensity. Gather these intensities on the master rank.
2. Create a new transition that can stream this array of intensities (for our current instrument this is a 1D array).
3. Implement a visualizer that can create an intensity plot from this (1 x N pixels, color-coded).

[lottiegreenwood]

Re https://github.com/DMSC-Instrument-Data/live-data-prototype/tree/instrument_view