feat: adding new stats

[brunocorrea23]

• Refactored the code a little bit to make it very easy to add new stats
• Added missing stats from proposal: fake business charts #202 (New items per day, New votes per day, New users per day)
• Changed the kv key for the 'visits per day' stats. Means we would lose the data we had before if there is no migration.
• UI for the /stats page needs some love
• Does not address bug: month value of visits is saved incorrectly #240 as it should be solved in fix: incorrect month of visits #241

[iuioiua]

Are you able to increase the spacing between graphs? They appear a little squished up.

[iuioiua]

The new layout on desktop is great! Are you able to fix the layout on smaller screens?

[brunocorrea23]

@iuioiua , I would appreciate some help here.
I noticed that the charts are not responsive, but I'm not sure how to fix this.
Can we tackle this on a next PR? I can create an issue. Also would like to add a tooltip, but also not sure how to do it.

[iuioiua]

Ok, I'll merge this when I can. Let's tackle the responsiveness issue after 👍🏾

[iuioiua]

Sorry for the delay. After making a tweak, LGTM for now! Note: I do think that some of this logic is a little difficult to understand. We can address this in a follow-up PR, alongside increasing the polish of the entire codebase for v1.