Changes to CI System and Binary Factory

[Ben Cooksley]

Hi all,

Over the past few days we have completed a series of changes to how
the Binary Factory and CI system operate, with a view to improving
scalability and security of the systems going forward.

As a consequence of these changes, we should now be able to scale
Flatpak builds across to multiple builders, more easily provision
Android signing keys, provide Android builds in our F-Droid testing
repository more rapidly and have the possibility of providing Snap
builds in the future.

Additionally, it will allow us to increase the number of FreeBSD and
Windows builders (from the existing 2 of each to 3 of each), and
should make the provisioning process for builders easier in the
future.

These changes however may have caused some breakages, particularly
with regards to Android packages, due to the nature of the changes
which have been introduced.

Should anyone have any issues, please let us know.

Cheers,
Ben Cooksley
KDE Sysadmin