Include 2025 workshop materials on resources tab.

[jonwzheng]

We usually update the Resources tab with the latest workshop. https://rmg.mit.edu/resources

This may be a good first issue for a new website dev to examine.

[rwest]

I just had someone email me asking for these. They found the videos, independently, on youtube, but were asking for the slides. Currently neither are linked from the RMG website.

[jonwzheng]

Yes, this would be good to revisit (and very quick to implement).
@KnathanM / @BonhyeokKoo could I please ask one of you to make this PR?
It should be quite similar to #278.