PointSourceLoss Update to v4

New version of the PointSourceLoss product with an update of "fractionCentral_to_3x3" and "fraction3x3_to_total". These datasets contain the flux fraction of the central spaxel with respect to the central 3x3 spaxels and the flux fraction of the central 3x3 spatial pixels with respect to the total flux.

The update takes into account an improvement of our knowledge of the PACS spectrometer beams, that was made possible by the improvement of the satellite pointing reconstruction.

Additional measurements were also included in the derivation of these new correction curves, namely the 'fine rasters' (0.5 arcsec step) were used, along with the original ones (2.5 arcsec step).

Changes

New ArrayDatasets "fractionCentral_to_3x3" and "fraction3x3_to_total". The change is documented in PACS-5053.