i18n options missing

[AlexAndBear]

Currently the svelte-jsoneditor is missing options for internationalization.

I am thinking of two ways, how this can be archived:

• The package ships translations and the developer can set them via a translation prop, eg translation: 'de-De'
• The package don't ship translations, but text can be overwritten eg: { texts: {searchFindText: 'Finden'}}