Integration with FABM

[plazzari]

In this work we plan to integrate OGSTM with FABM, with the primary goals to substitute the old BFM implementation with the modern FABM-BFM implementation.

[plazzari]

For FABM developments, it no longer makes much sense to keep namelist.passivetrc in its current form.

&NATTRC
ctrcnm(1)="N1p"
ctrcun(1)="mmol P/m3"
ctrmax(1)=1.000000e+0
ctr_hf(1)=1
/
Many things are now assigned directly by FABM; for example, ctrcnm and ctrcun are no longer needed.

It is still necessary to specify the assumed maximum value of a state variable ctrmax, whether it should be saved, and at what frequency a given variable should be stored.

Backward compatibility will be ensured when using BFM old, for which the legacy namelist.passivetrc remains valid.

For the new variable declaration, I would propose something like the following:

AVE_FREQ_1
N1_p, N3_n, ...
AVE_FREQ_2
N1_p .....