remove unavailable css and javascript

This change removed a lot of link to unavailable css and javascript. This should lower the number of requests and the amount of 404s.

Elements were removed using:

for f in *.html ; do sed -i '/yahoo-dom-event/d' "$f"; done
for f in *.html ; do sed -i '/js\/yui/d' "$f"; done
for f in *.html ; do sed -i '/js\/util.js/d' "$f"; done
for f in *.html ; do sed -i '/images\/favicon.ico/d' "$f"; done
for f in *.html ; do sed -i '/js\/comments.js/d' "$f"; done
for f in *.html ; do sed -i '/extensions\/Voting\/web\/style.css/d' "$f"; done

Bug: T343914