Basic/Start doesnt seem to match the codelab

According to the codelab what basic/start is supposed to load only the current days articles but what is actually happening is all 500 articles are being loaded at once without any pagination.

[4. Project overview](https://developer.android.com/codelabs/android-paging-basics#3)
> As mentioned earlier, the current articleStream in the repository only presents news for the current day. While this might be enough for some users, others might want to view older articles when they've scrolled through all available articles for the current day.

Start with the basic/start project and compare its behavior with the linked codelab's “Project overview” section. Reproduce the article loading behavior and trace the article stream and pagination entry points described there. Done means basic/start loads only the current day's articles as stated by the codelab, rather than all 500 articles at once.

Written by the indexing model from the issue text.