Enable a new responsive image style breakpoint for the xs devices

Problem/Motivation

Image style with 800px width size is displayed on the xs (mobile devices).

Proposed resolution

• Enable a new responsive image style breakpoint for the xs devices (1x screen-xs-max [all and (max-width: 575.98px)]) and use an image style with 600px width size.
• Make the 800px style only displayed on sm devices (tablet devices or larger than 576px).

Remaining tasks

• ✅ File an issue about this project
• ❌ Enable a new breakpoint for xs devices and change the sm breakpoint value and testing.
• ❌ Testing to ensure no regression
• ❌ Automated unit/functional testing coverage
• ❌ Developer Documentation support on feature change/addition
• ❌ User Guide Documentation support on feature change/addition
• ❌ Code review from 1 Varbase core team member
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A