Merge designer translations with modeler ones

As a Studio user, any translation entered in Designer is copied into Modeler so that I don't need to know where a given feature has to be translated

AC

• Copy happens during build time

Designer to Modeler copy

• When a translation file exists in Designer, an equivalent is created in a properties file on Modeler side
• When a translation key exists in Designer, it is copied in the properties file on Modeler side
• Any translation key that is copied over to Modeler is transformed in unicode format (https://stackoverflow.com/questions/27363614/java-properties-file-with-accented-characters#40620518)
• During key copy, if that key already exists in the Modeler properties file, it is left unchanged

Modeler to Designer copy

• When a translation file exists in Modeler, an equivalent is created in a json file on Designer side
• When a translation key exists in Modeler, it is copied in the json file on Designer side
• Any translation key that is copied over to Modeler is transformed from unicode format into the format used by Designer (UTF-8?)
• During key copy, if that key already exists in the Designer json file, it is left unchanged