Diagnostics to understand scale-interaction

A superticket to link diagnostics development associated with understanding scale-interaction.

The current spectral density diagnostics tells us THAT scales interact, however they do not detail how, when and where.

Further diagnostics need to be developed that help with expanding on the knowledge we gain from PSDs.

- wavelet
- energy spectra
- bispectra
- amplitude modulation

loosely connected are are developments linked to cellstats and FSS, eFSS, dFSS that use either feature tracking or recognition and partly give us histogram style information about cell radius and rain intensity.