Quick fix: branding update

[jasperhartong]

Goal

Make the smallest set of code-changes possible to style the current marketing website based on our new new brand guide.

Note: deploying this would require some orchestration

Changes

• New colours (e.g. in menu, headers)
• New logo
• Improved layout for pages
• Improved layout for team
• Improved layout for blog items
• (Unrelated) Bugfix: output valid JSON schema

Note: Not a lot of work done on the home page yet, might still want to do that if we include the new Cause Area section and embed the explainer video.

Todo

• [x] Update Favicon
• [x] Update JSON Schema image
• [x] Update social sharing image
• Later: Update the sans-serif font when it's picked

Deployment

• https://deploy-preview-87--givingwhatwecan-org.netlify.app/

Screenshots

og images

Only did a minimal re-branding of the og-images, didn't put much more thought in then just replacing the logo and colours for now.