[Tails-ux] new Greeter mockups (forget all the rest)

Hey,

The debate around the new Greeter was getting more attention lately but
it was hard to summarize. We also lacked a good solution for the
localization options. So we worked off-list together with tchou and Alan
and got something that pleases the three of us (at least!).

Images
======

First screen with persistence:

https://tails.boum.org/blueprint/greeter_revamp_UI/greeter-1st-screen-persistence.png

Top region of the first screen when the localization are saved:

https://tails.boum.org/blueprint/greeter_revamp_UI/greeter-1st-screen-langsaved.png

Advanced configuration screen:

https://tails.boum.org/blueprint/greeter_revamp_UI/greeter-advanced-screen.png

Guided configuration, Context:

https://tails.boum.org/blueprint/greeter_revamp_UI/greeter-guided-context.png

Notes: dashed boxes are hidden of flat buttons.

Last minute changes
===================

Tchou, you will see that a few things changed since we looked at them
with Alan:

- We had a doubt about the icon of the Start button, so we tried with a
different on that looks like a Play button.
- We want to try the first screen without the "Configure" buttons and
invisible buttons instead.
- We add back "Default configuration" on the Start button of the first
screen only.
- We replaced the password confirmation messages from the Advanced
configuration by icon instead of words.
- We change the "Effacer" link to a button. Alan says that in GNOME,
blue links are not used for actions. So we can't really do that if we
want to follow the HIG (maybe we don't).
- We brought back the short descriptions in the Advanced configuration.
The rationale here is that if you are ready to go through the Advanced
configuration you are actually looking for more detailed stuff.
- I changed the language icon to something that was less high.

All of this can be changed again of course.

Implementation phases
=====================

I also thought that we could schedule the implementation and release of
all this in three phases:

1. Revamp the first screen and Advanced configuration
2. Add the Guided configuration
3. Integrate the persistence configuration

I'm proposing this because I feel like we have been debating a lot on
the first two screens and that we have reached something that is worth
being tested and implemented. On the other hand, there is quite more
work needed on the Guided configuration:

  - There is nothing to configure bridges in there for the moment.
  - We have no context that matches what are the defaults (Spoofing:
    ON, Camouflage: OFF) and that feels weird.
  - The "Web café" context doesn't make it clear that you are using a
    public computer.
  - Rework the wordings.

But let's deal with that later on and move on with the implementation of
the first two screens, shall we?

Next steps
==========

If we do this, then the next steps could probably be:

1. Ask for a fresh reviews by Fiodor and Geoffrey?
2. Agree on a final set of icons.
3. Update all the other screens.
4. Do paper testing for phase 1.
5. Implement phase 1.

If we agree on this, I volunteer to create the relevant Redmine tickets.

--
sajolida