[Tails-ux] Decide if we want a dedicated browser for LAN

Hi UX team,

We decided during the last monthly meeting to disable LAN access from
Tor Browser. This is #7976. We should consider LAN as an hostile
environment and having it in the same browser as all the rest seems like
a bad idea.

Now we have to decide, and this is UX decision, whether we want:

- To move LAN activities to the Unsafe Browser (codename "combined")
- Have a dedicated browser for LAN (codename "separate")

We need to choose something that makes it both clear what you can expect
from those browsers and easy to get your stuff done without using the
wrong browser by mistake.

Note that this is also highly related to #7774: Rename the Unsafe Web
Browser to express its supported usecase more clearly. And we should
probably solve both things at once.

Here are some of the arguments heard during the meeting:

anonym: "LAN Browser" would only be a sub-set (capability-wise) of the
Unsafe Browser since captive portals sometimes require LAN access, so it
seems point-less to me.

intrigeri: I think the way users see things is more important. They
don't care if "Local network web browser" is a subset of Unsafe Browser.

sajolida: from a user point of view it kind of make sense to have the
same scary theme and "unsafe" feeling on the LAN if you consider this as
a way of saying "hey, here you are not anonymous".

intrigeri: we already have 2 special-purposes browsers (Unsafe and I2P),
and a proposed branch that makes the whole thing quite nice and
maintainable.

intrigeri: could be a good occasion to try documentation-driven-dev. the
easiest to document will be the easiest for user, I suppose.

anonym: more browsers with specific purposes => more things for the user
to keep in their heads w.r.t. browsing, which is something they probably
would expect to only have *one* browser for. I don't think these
separations we make are intuitive unless you have some pretty deep
knowledge about Tor, networks and the threats model we have here.

intrigeri: I agree. OTOH, once you already have educated users to pick
among two browsers, going to 3 isn't that much a big deal, perhaps.

I can see a small tendency towards combining Unsafe and LAN. So, shall
we try to find UX arguments in favor of separating them maybe? Then we
can count points :)

--
sajolida