Provide deploy preview links for each language

[fkohrt]

Is your feature request related to a problem? Please describe.

Multilingual sites tend to have a language code inside their path, such as https://example.org/en/about/. This is also the default behaviour for Hugo sites.

Describe the solution you'd like

Make available a {{lang}} template tag for the preview_path template. When internationalization is enabled and preview_path uses tags that are configured individually for each translation, provide multiple deploy preview links.

Describe alternatives you've considered

Only linking to the default language.

[martinjagodic]

I would love to see this implemented