iHAMOCC towards the NorESM2.3 release

[jmaerz]

This issue tracks the steps taken on the iHAMOCC side towards the NorESM2.3 version as requested in:
https://github.com/NorESMhub/NorESM/milestone/4

On the iHAMOCC side, we intend to incorporate:

1. the extended nitrogen cycle (optional)
2. cyanobacteria growth (bluefix) only in euphotic zone (not throughout MLD) as optional (switch leuphotic_cya)
3. the M⁴AGO sinking scheme for marine particles (Maerz et al. 2020) as optional
4. preformed silicate tracer
5. support for BLOM mks units - since Making MKS units default #344 default in BLOM
6. online sediment spinup as default
7. group call to apply_fedep together with other routines for external inputs #350

Carbon isotopes were already included as optional in the NorESM2.1 release (and they stay optional in NorESM2.3).

Points 1-4 will be included when merging the extended nitrogen cycle into master #269 .
Points 5-6 are already included in the master of BLOM.

Currently, we aim at merging the extNcycle-M4AGO branch into master in the last days of May 2024.

[TomasTorsvik]

The additions to NorESM2.3 from iHAMOCC is now completed.