update tags when calculating proportional concentrations

[cdemulde]

When using calc_tot_prop, new columns are created, but these do not get a tag in the self.meta_valid and/or self.meta_filled dataframes. This is important, especially in the case where the filled data is further used and it's important to know what is real data and what is filled.

Include the addition of a new column to the self.meta_valid/meta_filled dataframes in the calc_tot_prop function. This should be a combination of the columns that the proportional concentration is calculated from, making that wherever the tag is not 'original', something else is used.