Fix metadata issues

[andrewsosa]

From #46, we updated the metadata for the new iteration, but there's some issues:

• [x] Favicon doesn't work
• [x] og:image and twitter:image are out of date

We'll need to source assets from design to replace these, alternatively I can make them.

[andrewsosa]

Favicon in 0505c94d73dcfb2ac0cd968ee05a25093e017423, OG images in a4b62bbafd70d7ef0b9ae17fda640cff3deb3955