Improve aspect data processing

[FredSchuller]

Here's a list of things to-do to improve the processing of SAS data.

Critical before next GSW release

• implement usage of appropriate simulated data-cube depending on solar image radius. This will rely on a look-up table that gives the name of the file for a given range of solar image radius. TBD where to store these files and the look-up table.
• if no solution can be found, return the "default" (average) solution, corrected for SolO's nominal pointing, instead of NaNs. Then, use the "error message" field to provide some informative diagnostic
• improve on error handling and reporting
• improve on calibration / re-scaling of the signals, so that observed signals match simulated ones

To keep in mind for later

• check whether the time stamps (and therefore the spacecraft attitude data) need to be shifted by 32s
• change the output to be consistent with the implementation in the imaging pipeline (X_stix, Y_stix) instead of (Y_srf, Z_srf)
• decide if it's required to refine the solution found for each measurement, by computing simulated data over a small parameter space around the found solution for the exact value of the solar image radius at that time

[samaloney]

@FredSchuller update?