Tor Browser: block JavaScript coming the news section of our website.

This limits a little bit the attack surface that's implied by having our website
as the default Tor Browser's homepage, and thus loaded by most Tails users soon
after startup: a non-negligible proportion of Tor Browser security issues don't
apply if JavaScript is disabled.

Still, as said on https://labs.riseup.net/code/issues/7023#note-7, this is not
a complete solution. Tackling this problem for real needs more research, to find
a way to convey important project news to our users without having them
systematically load our website.

Refs: #7023