Redirect firefox/IE comparison page

[stephaniehobson]

This page is out of date and not a significant source of conversions. It can be removed and redirect to the Edge comparison.

• Remove /firefox/browsers/compare/ie/ and associated assets
• Remove links to it from around the site (compare subnav, look for others)
• Redirect /firefox/browsers/compare/ie/ to /firefox/browsers/compare/edge/

[reemhamz]

We're probably going to also need a new graphic for the hero image so it removes IE:

https://www.mozilla.org/en-US/firefox/browsers/compare/

[stephaniehobson]

@reemhamz I'll note that in the Asana ticket for the page re-design. It's not a blocker for this Issue :)

Also, if you would like to fix to the image that's okay too.