[CH EMED EPR] Add support for converting the FOPH indicationCode once added to CH EMED EPR

[dvribeira]

See CARA-ch/ch-emed-epr#103

[dvribeira]

This will be added as an extension at the level of CH Core, see hl7ch/ch-core#432

Will be added to Husky once we have a new release of the IGs