Tomography Ingest: bring "data_simple" up a level

[dylanmcreynolds]

A user had a use case for finding a field, but it felt hidden. Unfortunately, I couldn't find what I needed
/measurement/instrument/detector/exposure_time
because I forgot that it went into an easy-to-miss sub-section collapsed under "data_sample" so I downloaded the data set and used hdfview anyway. Now I have remembered that that field exists, but can we just list it so that it isn't collapsed by default so it's not so hidden away, so users can find it easily?

This would be easy to implement. Since this is an abbreviated field (representing samples of data not the full data, which could easily be too large), I put it in data_sample to highlight that it was a sampling.