Update Mapbox API URLs and IDs in tutorials

[lyzidiamond]

• Updates all references and URLs to the Mapbox v4 API
• Adds a Mapbox access token associated with the mapbox Mapbox account to make v4 API requests work
• Replaces all examples map IDs with mapbox map IDs (just mapbox.light and mapbox.streets)

Some things to note:

• This is a straight up find-and-replace, and it will be annoying (but not impossible) when we inevitably have to rotate out the access token. Curious to see how often we have to do this -- I will keep an eye on traffic/referrers.
• I did not change any of the tutorial language, just the URLs. If necessary, I can update language in the tutorials to add info about access tokens.

🎤 🐙 🌜

[mourner]

semicolon

[mourner]

Thanks a lot for the PR! Aside for minor comments, looks good to me!

[lyzidiamond]

@mourner alright, I think I hit everything you mentioned. Feel free to merge or let me know if there's anything else to change!