update sensitivity loss correction with updated tables

[falkben]

Alice provided updated tables with the correction factors and we should update our correction to use that

The current correction is here in code:

DRESSCode/dresscode/corrections.py

Line 222 in 29e4323

zerocorr = 1 + param1 * years_passed + param2 * years_passed ** 2

We need to replace the polynomial with lookups into the table. Where the days are "since 1st Jan 2005". Second column is the new average count rate; the correction is the inverse of this number and is in the third column.

The lookup tables are somewhere in the caldb files however Alice sent us these extracted:

caldb_values_w1_12_out.txt
caldb_values_m2_12_out.txt
caldb_values_w2_12_out.txt
caldb_values_wh_12_out.txt