Open Graph cards (previews for X/twitter)

[aaronmgdr]

Problem

the previews on twitter suck.

Solution

1. Create a good default/ home page preview image
2. create images for each of the main sections
3. for delegate/$address pages can we use the image that was uploaded as the preview (or generate one on build)
4. for governance proposals create an image with words like "Vote Celo Governance"

all cards MUST look good on both dark and light mode. (IE dont use transparent images)

[aaronmgdr]

this involves some graphic design. :)