Add support for CookieScript "Pre-Production" and "Staging" mode

Problem/Motivation

CookieScript has introduced new "Pre-Production" and "Staging" features that allows a separate banner configuration/script to be used on non-production environments.

See: https://cookie-script.com/news/cookiescript-new-cookie-banner-design-staging

Currently the module only allows configuring a single script.

Proposed resolution

Add a new optional setting for the "Pre-Production" and "Staging" mode.