refacto parameters

README_API.md

Simulation_engine/reforms.py

Simulation_engine/simulate_pop_from_reform.py

reformes/reformePLF_2020.py

reformes/reformePLF_2021.py

reformes/reformePLF_2022.py

reformes/reformePLF_2023.py

server/api.yaml

tests/Simulation_engine/test_reforms_impot_revenu.py

tests/Simulation_engine/test_simulate_pop_from_reform.py

tests/server/handlers/test_cas_types.py

tests/server/stress/payload.json