Make it clearer what job dailyStatsJob is about

[Martinsos]

• Looking at it, it is not very clear to me what it does.
• I went to its JS implementation, but even there it wasn’t really clear what it does (without looking deeper into it).

TODO: Comment it (in main.wasp and/or in its JS file), to make it clear what it is about, what it does, why do I need it. I want to understand if I can delete it or not, what it is connected to.