bug#47152: elpa.gnu.org incompatible with librejs

[email]

The packages page <https://elpa.gnu.org/packages/>
is blocked by LibreJS because the included javascript
is not clearly licensed. It all appears to be free
jQuery and components related to filtering; it just
needs clear marking.

The page is simple enough that the browsers `C-f` is
sufficient filtering to simply remove the javascript. 
If you want to keep it around <https://melpa.org/jslicense.html>
provides a good example of how to clearly state the
licenses for compatibility with LibreJS.