Separate out diagnostics display by report type

[esheehan-gsl]

Describe the motiviation for the change

Different report types (marine, airplane, station, etc.) have different qualities, so it is useful to see the distributions of $O - B$ on a per-type basis, not all lumped together

Describe the change

Separate the distributions by observation type instead of lumping them all together.

[esheehan-gsl]

Suggested by Ming Hu in a demo on 15 November 2023.