refactor: article images conversions

[alfonsobries]

Summary

https://app.clickup.com/t/865d7nd1u

I decided to solve it in a simple way:

• Keeping the large image for the article view (1000px).
• Using a medium image for article cards. The measurement comes from the widest width at which it can be displayed (on a small screen just before switching to a medium screen, 639px screen).
• Small image for the list view based on the size used on medium screens and up.

As a reference, we used a much more complex alternative on MSQ that resulted in a lot of conversions, and we used the screen size to decide which image to use (for example, on a large screen, it might appear smaller than on a medium one due to the number of columns). In my opinion, that was an overkill solution that made it difficult to maintain and arguably didn't offer any tangible benefits.

This is just an opinion, of course, and is open to discussion.

Checklist

• I checked my UI changes against the design and there are no notable differences
• I checked my UI changes for any responsiveness issues
• I checked my (code) changes for obvious issues, debug statements and commented code
• I opened a corresponding card on Clickup for any remaining TODOs in my code
• I added a short description on how to test this PR (if necessary)
• I added a storybook entry for the component that was added (if necessary)
• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged