* Make `enfant_a_charge` usable in monthly mode so that we can re-use it in mes-aides, and broaden its definition so that in includes children in `garde_alternee`.
* Refactor and test nbF, nbG, nbH, nbI.
* Deprecate:
* `nombre_enfants_a_charge_menage`
* `enfant_a_charge_invalide`
* `enfant_a_charge_garde_alternee`
* `enfant_a_charge_garde_alternee_invalide`
* Rename:
* `statmarit` -> `statut_marital`
* `marpac` -> `maries_ou_pacses`
* `celdiv` -> `celibataire_ou_divorce`
* `jveuf` -> `jeune_veuf`