Child improvements

- Make the tree view editable in child_translated_values_view.xml
- Make "get infos" button retreive basic info or if project doesn't exists, create it and retreive basic info 
- Add French, German and Italian descriptions in project_compassion_view.xml
- Add French, German and Italian country names in country_compassion.py
- Make project_compassion_view.xml (the view) as clear as possible
- Create English child description (child_description_en.py)
- Create Italian child description (child_description_it.py)
- Refactor child_descriptions_en|de|it.py 
Since _gen_list_string is the same method as in the French wizard, and is called here always with the same parameters, I propose one of the following changes. You can choose which one you prefer:

1. You remove all _gen_list_string methods from the localized files and you put a class method in file child_description_wizard.py that you can call from all files (using from child_description_wizard import child_description_wizard)
2. You keep all the methods in the localized files (fr, it, en, de) but you remove the parameters from the method so that it becomes `def _gen_list_string(cls, list)` and you put the separators inside the method, so that you can call it without giving each time the same parameters.