Build challenge gauge widget for HTML/CMS integration

[Tirodem]

Use cases

• Template the challenge gauge #107
• Manage a challenge gauge #108
• Increment challenge score when a product is ordered & paid #110
• As a bootik owner, I want to be able to integrate the widget of one of my challenge on a CMS page #114
• Manage recurring challenges #109 (not MVP)
• As a bootik owner, I want to be able to integrate the widget of one of my challenge on a Product page #115 (not MVP)