Bump github-pages to v28

Signed-off-by: David Celis <me@davidcel.is>
Change the layout in feed.xml to null

This will squelch a warning (see jekyll/jekyll#2712)

Signed-off-by: David Celis <me@davidcel.is>
Update profile picture and favicons

Signed-off-by: David Celis <me@davidcel.is>
Update colors for the new images

Signed-off-by: David Celis <me@davidcel.is>