[PureOS] PureOS 2019/07/14 images ready for testing

[Matthias Klumpp]

Hi!
Primarily due to an initramfs permission issue where reading disk
encryption keys from the initramfs was possible in certain
configurations[1], but also because the previous images were getting
old, we have new PureOS installation images for testing.

Thinks to look at, as always:
 * Does the image boot cleanly?
 * Does the Live installer work?
 * Does the OEM installer work?
 * Does the OEM initial setup work as expected?
 * Does the respective desktop function as expected?
 * Any noticeable bugs/regressions?

You can find the images for the respective flavors here:

GNOME Live: https://downloads.puri.sm/live/gnome/2019-07-14/
GNOME OEM: https://downloads.puri.sm/oem/gnome/2019-07-14/
Plasma Live: https://downloads.puri.sm/live/plasma/2019-07-14/

I already tested the images and found no noticeable issues, but having
more eyes on them before we change the default download links is
always good.
Happy testing!
Cheers,
    Matthias

[1]: https://calamares.io/calamares-cve-2019/