Add i18n Support and Translate to German

[s3n-w6i]

This PR adds support for i18n on the calendar page and contributes a translation. It does not include the i18n setup and translation of the settings page.

Thanks for this awesome plugin :)

[LuisRodriguezLD]

Thank you for your PR. It looks great but could you add instructions on how to switch locales?

[s3n-w6i]

Sure. Add 'de' to locale config the backend config like so: https://docs.strapi.io/developer-docs/latest/development/admin-customization.html#configuration-options (Scroll down to "Locales")

Rebuild the admin panel, go to profile settings (click on your username in the Bottom left) and select "German" for Display language.

[LuisRodriguezLD]

Thanks for adding the instructions but I meant having them inside the README.md

It seems like the calendar picker is not localized. (see image) Also, what's the effort on translating the settings page as well? I feel this could benefit a lot of users and it will be easier to add more languages

[s3n-w6i]

Hm, I personally don't think it makes sense to put that in the README. As a developer you don't change that admin config because you want the calendar plugin to be in your language. You rather change it, because you want Strapi as a whole to be available in your language. Therefore, you would rather look for information on how to do that in Strapi's docs, as opposed to here.

The missing translation of the Date Picker is something that depends on Strapi's Design System to be translated. Right now, the components are not translated. Nothing I can do about that here, other than maybe waiting for this PR: strapi/design-system#688

The settings page is now fully translated.

[LuisRodriguezLD]

You are right. I guess I just wanted to show somewhere that the plugin is now localized in German. I'm good to merge once you resolve the failing action.

[s3n-w6i]

Lint passes now locally for me :)