Evaluate web fingerprint

Originally created by Tails on #5362 (Redmine)

Now that we use Torbrowser patches (#5798 (closed)), we can reconsider the browser fingerprinting issue.

We should evaluate the Tails web browser fingerprint.

• Extensions: FoxyProxy, Cookie Monster, You tube video downloader, download manager (not implemented yet), Adblock.
• Would we be ready to stick to or synchronize our add-ons with Torbrowser? (e.g Adblock is useful)
• "Tor Browser disabling Javascript anonymity set reduction" thread on tor-talk

team: jvoisin, spriver?

Related issues

• Related to #5706 (closed)