i18n for health endpoint strings

[isaacvr]

/health now returns some strings like display_name and coin_hours_display_name. These values need to be translatable to different languages.

In this case, since these values are configured through fiber.toml, we can either configure additional translations in fiber.toml or add additional file(s) which maps english strings to their translations.

The Accept-Language header can be used by clients to request the language.