Add localisation via XLIFF files

[spwoodcock]

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

• It would be great to have localisation support in as many languages as possible.
• Translations can be done by the community via Weblate.
• This will output XLIFF files that can be used in these components.

Describe the solution you'd like

Add https://lit.dev/docs/localization/overview to generate localised components from the XLIFF file.

Describe alternatives you've considered

GNU gettext PO files, but Lit doesn't support them out of the box.

Additional context

Translations will be reused across all tools, including these components, TM, FMTM, etc.