Remove SampleVolume_m3 column from CPR phytoplankton abundance files

[clairedavies]

Please remove SampleVolume_m3 column from CPR phytoplankton abundance & biovolume files. Because of the way that we count these silks this column is confusing people who are not familiar with the data methods. It is also only required when used with count data, abundance / biovolume has already taken this into account.
Remove from:
CPR Phytoplankton Abundance – Higher Taxonomic Groups
CPR Phytoplankton Abundance – Genus Data
CPR Phytoplankton Abundance – Species Data
CPR Phytoplankton Abundance – Raw Data
CPR Phytoplankton Biovolume – Higher Taxonomic Groups
CPR Phytoplankton Biovolume – Genus Data
CPR Phytoplankton Biovolume – Species Data
CPR Phytoplankton Biovolume – Raw Data

We can leave it in the zooplankton collection, as although it is not needed, it is not confusing as we count this data in a more standard manner.
Thank you

[leonardolaiolo]

To do for Leo: update format consistenstly with backlog