Make use of a third party service for translations

[Impre-visible]

Hi everyone, I merged some pull requests for the german translation, and I think it's way to hard to easily translate as someone that never used github.

So I'm thinking about using a third-party app/service to easily manage invoicerr translations/localizations.

I was thinking about Weblate, but sadly the project isn't old enough. And Tolgee is very limited with the free plan.

If someone knows a good way to easily provide a UI to manage the translations key that would be awesome.

While that, we'll wait for the project to be 3 month old to ask for a free Weblate hosting.