Rename the Unsafe Web Browser to express its supported usecase more clearly

Originally created by @intrigeri on #7774 (Redmine)

While doing user support, it’s clear that many users misunderstand what the Unsafe Browser is for. I don’t think it’s particularly surprising:

• the Unsafe Browser doc doesn’t explicitly tell that it’s only meant to connect to captive portals
• the launcher’s title is “Unsafe Web Browser”, which might hint people that one can browse the web with it
• the launcher’s tooltip is “Browse the World Wide Web without anonymity”, same problem as the title

I’m starting to think that we should simply rename the “Unsafe Web Browser” to something that clearly expresses what its only supported usecase is. E.g. “Log into a captive portal”, or whatever.

This rationale changed quite a bit now that we decided to move LAN traffic to this same browser. Naming it something about captive portals only wouldn’t work and we need a more generic name.

Still, it might be worth trying to improve on that.

Related issues

• Related to #7772 (closed)
• Related to #7976 (closed)