Revise How to run a model main page

[atteggiani]

• Added cards to "How to run a model" overview page.
• Removed '.configuration-card' class (that only set height of card to 15em) and replaced it with inline CSS for the respective cards.
  This because we will change the height of different rectangular cards depending on the pages they are on, so it might be better just to taylor the heights of each by providing inline CSS with them.
• Removed "object-fit: cover " from the '.rectangular-img' class (may remove that class completely in some future PR) and added the already existing ".img-cover" class to the respective elements.

[github-actions]

PR Preview Action v2.1.1
🛫 Deployed preview to https://access-hive.github.io/pr-preview/pr-455/
on branch gh-pages at 2023-07-20 01:53 UTC

[KAUR1984]

Thanks for the fixes @atteggiani !