Add missing content pages

🎨 Design

This needs to be mocked up. Please do not proceed until we reach a design agreement in this issue, and we have a mockup.

Tasks

• [ ] Wiki homepage
• [ ] Open Food Facts & Science
• [ ] Made Near Me https://madenear.me/ (with a Tablet-only warning)
• [ ] How Much Sugar.in https://howmuchsugar.in/ (with a Tablet-only warning)
• [ ] Open Food Facts & the Nutri-Score: https://world.openfoodfacts.org/open-food-facts-and-the-nutriscore
• [ ] Help with Development: https://world.openfoodfacts.org/development
• [ ] https://world.openfoodfacts.org/science