Import zone colors from an FMU stratigraphy.json file located next to the
formation files, and import formation zones from a yaml file.
- Add RifFormationNamesFileParser and move the layer zone table, yaml and
stratigraphy.json parsers there from RifFormationNamesReader.
- Return std::expected from convertStringToColor.
- Prefer zonation_ecl_map yaml when several yaml files are present, and ignore
other yaml files.
- Document the FMU location of the formation files.
- Add unit tests and test data for fmu, malformed and missing-color inputs.
Issues: #13889, #13888
