Investigate the outgoing network connections of Etcher

Originally created by @Anonymous on #16381 (Redmine)

It looks like Etcher / Balena now shows users advertisements.. :(((((
https://github.com/balena-io/etcher/issues/2599
Also reported here: https://www.nextinpact.com/news/107525-tails-3-12-fait-evoluer-sa-methode-dinstallation-quels-changements-concrets.htm (credentials available via Tails press team).

I think we need to investigate this and eventually change tools :(

(:sajolida: wants to track this)

Next step: test other tools we could switch to, see linked issues.