Kirsty Bryce

## Context In this PR we are adding the `Content Container` widget to backpack, as `BpkContentCards`. This component consists of a header and cards, each card with an image, header,...

## Description ### JIRA: https://skyscanner.atlassian.net/browse/QUAR-425 We want to use the inset banner component in our ads in web like we already [do for our ads in apps](https://www.skyscanner.design/latest/components/inset-banner/compose-SIxM16J2). In this PR...