Archiving of profile pages

[jcushman]

Archiving a user's page, like twitter.com/<handle>, currently only captures the top few tweets by that user. This is because those pages are formatted differently than thread URLs, and will require a different workaround to render tweets loaded by infinite scroll. We can't fetch all the tweets for a user page within the capture timeout window, but it would be good to fetch the first 50 or so.