Added support for featured blog posts (alshedivat#1498)

Implementing alshedivat#1440. Still not sure if the year should be shown there or
not. Also, I limited to be displayed at least 2 at most 3 elements on
the row of featured blog posts, since when having only 1 featured post
the card would occupy the whole row (and it looks weird). What do you
think @alshedivat? Also, idk how to force the cards to have the same
height. I think it would look nicer, but my lack of web dev skills made
a difference here.

Some current screenshots:


![image](https://github.com/alshedivat/al-folio/assets/31376482/11b280dd-70b6-4bc4-84b6-987aa6412d55)


![image](https://github.com/alshedivat/al-folio/assets/31376482/d94aac41-246d-4b4e-afd0-161aab5a9b88)

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Signed-off-by: George Araujo <[email protected]>
Co-authored-by: Maruan <[email protected]>