Introduce a required cookie_policy_url alongside the existing
privacy_policy_url (now optional) so banners can link directly to a
dedicated cookie policy — a compliance best practice recommended by
CNIL, ICO, and the EDPB. Existing rows are seeded from their current
privacy_policy_url value.
Both {{cookie_policy_link}} and {{privacy_policy_link}} placeholders
are supported independently in banner description translations.
Signed-off-by: Émile Ré <emile@getprobo.com>
