Lets stick to the default behavior of Tails Installer, which is to use
syslinux without --force and --stupid.

We don't implement the same workarounds for udisks race conditions as
Tails Installer does, because there is little chance that we hit these
issues in this context (no slow bare metal flash medium, no CPU eaten
by USB emulation).

We don't have to do the filesystem verification Tails Installer does,
because unlike Tails Installer we always create a new filesystem.

We don't want to support overlay and kernel_args options, those are
probably Fedora-isms.

Drop pkexec dependencies from build dependencies (we run live-boot
as root during the build).

Use ISO size as estimate of its content.

I can't tell whether "Size that the system partition will be created larger
than" is correct English but regardless, I had a hard time parsing it.

... instead of live-realpremount, because the latter is actually
executed after /dev/sda1 is already mounted

This file was made translatable in this commit (through a .in file added
alongside, and its addition to po/POTFILES.in):
| commit 6818d283
| Author: Alan <alan@boum.org>
| Date:   Sun Aug 26 12:59:10 2018 +0000
|
|     ASP: make policykit action translatable
|
|     Will-fix: #14598

but the target script wasn't removed from git accordingly. Let's fix this.

Merge remote-tracking branch 'origin/bugfix/15838-asp-fix-non-blocking-issues' into stable (Fix-committed: #15983)

Refs: #15838

These are set when privacy.spoof_english is changed to 2, but not if it
is already set to 2 when firefox is started. So we set them ourselves to
fix the spoofing.