fix spacing issues on nextjs branch

[gumaerc]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/5745

Description (What does it do?)

This PR addresses some spacing issues between the main and nextjs branches:

• #app-container styles moved to PageWrapper
• fixed padding on the home page hero image
• fixed search input padding issue

Screenshots (if appropriate):

How can this be tested?

• Spin up this branch of mit-learn (If you are coming from main you will need to rebuild your containers)
• Visit the home page at http://localhost:8062/
• Verify that the styles described above and in the issue match production (https://learn.mit.edu)

[shanbady]

looking good 👍