Make Gramps loader messages translatable

[bartfeenstra]

GrampsLoader.load_tree() in https://github.com/bartfeenstra/betty/blob/0.3.x/betty/gramps/loader.py#L138 logs several hardcoded messages. These should be translatable.

Definition of Done

• Make all log messages translatable through the gettext methods o. self._localizer
• Remove the @todo comment

[RomainDereu]

@bartfeenstra Hi, I'd like to work on this if help is needed!

[bartfeenstra]

Hi, and welcome! This has been picked up by https://github.com/bartfeenstra/betty/pull/1238 for now. If you'd like to help out, there as some other good first issues you may find interesting 😊

[bartfeenstra]

This issue is now available for anyone to pick up again 🙂