replacing toys models with a single general toy model

See merge request !2

toy model  supports YAML file input for ifs, nemo, and runoff via argument parsing, while also addressing the formatting issue in the YAML input file.

the toy model read the yamel file and works with  oasis - only tested for ifs, todo:  refactor, restructure in modules, logging and error handling

several changes for co2box model in tests/ : use global (not hemispheric) co2 box model and deactivate co2 emissions in IFS_mock.py ; updates to convert-ece4pyreader-grids.sh

several changes for co2box model in sources/data-coupler/ : various bugfixes and more logging ; rename oasisIn to oasisOut ; allow option to accumulate and add fields (e.g. emissions) or only read field for first timestep (e.g. initial co2) ; add constants and named scale factors (e.g. co2_ppm_to_mass) ; use global (not hemispheric) co2 box model

basic refactoring with new OasisOutVar (handling update and send internally) and renaming DataCouplerVar class to FileInputVar

add DataCouplerCO2Box.py and associated namelist and namcouple, identical in functionality to DataCouplerAMIP.py

add support for co2 concentration and sending data from multiple variable to...

See merge request !1

add support for co2 concentration and sending data from multiple variable to one oasis var (e.g. CO2-em-anthro and CO2-em-AIR-anthro)