Replace raphael-rails with raphael.js and split it from the rest of the JS
## What does this MR do?
Removes raphael.js and its related libraries from the default JS bundle.
It also removes raphael-rails because the gem is unmaintained and – for whatever reason – didn't want to cooperate with the way I was trying to require it.
This brings the default (compressed and minified) application.js from 354KB after the d3 MR (!4394) down to 324KB.
## Are there points in the code the reviewer needs to double check?
That tests pass and that there aren't errors on any pages (especially the Network page).
## Why was this MR needed?
It's only used on the Network page and was using way too much bandwidth for just one page.
## What are the relevant issue numbers?
#14372#13165
Follow-up to !4394 and !4516.
cc: @jschatz1
See merge request !4519
