At the moment we are not considering having a replacement of the
/download page, so since we are renaming this file anyway let's move it
where it belongs: next to the other steps.

We want to rename them as .html to benefit from po4a on translations so
we remove them first, before adding them again (to prevent breaking the
website).

This reverts commit bdcbaa33.

This reverts commit 3ad2b1bd.

Conflicts:
	wiki/src/download.inline.mdwn
	wiki/src/install/v1/Tails/i386/stable/latest.yml

We'll do a major release on the following one (March 8) since 2.0 will
be frozen in December 11.

This allows having 2.0 (even) as a major release. It's also more
consistent with other project, such as GNOME, where even numbers mean
"big" releases with significant changes for the user.

It's the remaining biggest optimization suggested by PageSpeed about our
home page.

While we should be careful not to blindly rewrite all images from our
Git repo as it may grow .git with little benefit, banner.png is on every
page of our website, so optimizing it by more than 50% can be worth it.

We'll do one or two betas, but only once RC.