Fixes #968: Dependency calculation took a long time for `postmarketos-ui-plasma-mobile`

* Added redscreen kernel patch and xorg config
* Moved weston and x11 specific config to subpackage
* Removed deviceinfo_weston_pixman_type for hammerhead
* Added msm-fb-refresher to hammerhead

* Re-add powerdevil and polkit-kde-agent as runtime deps to postmarketos-ui-plasma-mobile
* Add kwinrc to start applications maximized

* Upgrade Qt libs to 5.9.3
* Add test case to make sure we are always in sync with Alpine's QT
and update qt5-qtsensors, too.
* Remove qt5-qtquickcontrols2 (it's in Alpine now)

It made problems, see #956 and #952. Originally this was added, so
our plasma mobile packaging - which targets wayland - doesn't need
to depend on X11 stuff. And because dbus-x11 caused a 1 minute
wait for an X server (#377).

We have yet to figure out if this problem returns, but even if that
happens, it's better than having it completely broken. And we can
probably figure out a better way to fix it (for real).

Fixes #949.

Contains everything from #940, except on top of master now.
Also added a postmarketos-ui-luna package to be a meta-
package for all of the Luna work.

Every component included here builds & runs, but isn't
functional without a handful more packages.

See also: #698

This is a follow-up to #935.

* fix regression #941: pmbootstrap doesn't automatically pick the
  right architecture for building when none is specified
* remove obsolete --noarch-arch parameter

* Add postmarketos-ui-plasma-mobile
* Add more required packages
* Upgrade plasma sources
* Modernize APKBUILDs
* Make it run in general
* Support RGB32 framebuffer with BGR order (thanks @zhuowei!)

* Rename pmb/build/package.py to pmb/build/_package.py, so we can
  access the functions it contains in testcases, and still use
  pmb.build.package()
* Refactor the entire file. Instead of one big function that does
  too many things, we have many small ones now, that are tested
  in the testsuite and easier to modify
* Whenever building a package, pmbootstrap does not only build and
  install the "makedepends" (like we did before), now it does the
  same for the "depends". That's required to be compatible with
  abuild. The old behavior can still be used with 'pmbootstrap
  build --ignore-depends'.
* Because of that change, noarch packages can no longer be built in
  the native chroot if we need them for a foreign chroot. A device-
  package depending on a kernel would pull in the same kernel for
  the native architecture otherwise.
* Running 'pmbootstrap build device-...' without '--ignore-depends'
  and without a matching '--arch' displays a note that explains
  this change to the user and tells how to use it instead.
* Noarch packages no longer get symlinked. That was only
  implemented for packages built in the native chroot, and now that
  is not always the case anymore. Symlinking these packages creates
  packages with broken dependencies anyway (e.g.
  device-samsung-i9100 can't be installed in x86_64, because
  linux-samsung-i9100 is armhf only).
* Rename "carch" to "arch" wherever used. Naming it "carch"
  sometimes is confusing with no benefit.
* Add a testcase for the aarch64 qemu workaround (because it failed
  first and I needed to know for sure if it is working again).
* Improved some verbose logging, which helped with development of
  this feature.
* Removed the old "build" test case (which was disabled in
  testcases_fast.sh) as the new "build_package" test case covers its
  functionallity.
* Only build indexes if the packages folder exists for that arch (Travis
  couldn't run a test case otherwise)

* add my own build key
* enable the repo in the config
* update the README file
* Adjust testcase, that validates the keys and enable it in testcases_fast.sh
* Only save/load keys to/from the config file, which we ask for during
  'pmbootstrap init', so the binary repo gets used even if a config file
  already exists (this also removes a workaround, that deletes the work
  folder path from the config dictionary before writing it)
* Download missing APKINDEX.tar.gz files with Python code, before
  attempting to build packages (so we know which ones aleady exist in
  the binary packages repository)
* Consider APKINDEX files older than 4 hours as outdated and download
  them again (also in Python code)
* Provide 'pmbootstrap update' to force-update the APKINDEX files
* Travis: more logging output on failure
* Only allow keys from config_keys to be used by "pmbootstrap config"