Add Additional Resources/Lessons to Mod 3 lesson page

[juliet-e]

There were some additional lessons in BE mod 2 and 3 that we could port over to the new curriculum site as resources for students. This card will involve:

• Moving the Joins part 2 lesson to the index page (and update links to set-list links to point to set-list-api repo, which has the same joins-homework branch)
• Review other old lessons and bring over any additional resources that could be helpful for students in Mod 3 (or consider adding them as async lessons?)