gnu: yaml-cpp: Import missing module.

This is a followup to commit f50f4ae454ab8e32c3b43541c493ba652ec03a05.

* gnu/packages/serialization.scm: Import python module.

gnu: gpgmepp: Import missing modules.

This is a followup to commit 30ffab50063c2cc8a4523d2eb110be9ebe388f51.

* gnu/packages/kde-frameworks.scm: Import boost and gnupg modules.

gnu: gstreamer: Use license: prefix.

* gnu/packages/gstreamer.scm (define-module): Import guix licenses with
(orc): Likewise.
(gstreamer): Likewise.
(gst-plugins-base): Likewise.
(gst-plugins-good): Likewise.
(gst-plugins-bad): Likewise.
(gst-plugins-ugly): Likewise.
(gst-libav): Likewise.
(python-gst): Likewise.

gnu: qt: Update qt to 5.7.0.

* gnu/packages/qt.scm
(qtbase): Update it.
(qtsvg): Update it.
(qtimageformats): Update it.
(qtx11extras): Update it.
(qtxmlpatterns): Update it.
(qtdeclarative): Update it.
(qtconnectivity): Update it.
(qtwebsockets): Update it.
(qtsensors): Update it.
(qtmultimedia): Update it.
(qtwayland): Update it.
(qtserialport): Update it.
(qtwebchannel): Update it.
(qtlocation): Update it.
(qttools): Update it.
(qtscript): Update it.
(qtquickcontrols): Update it.
(qtquickcontrols2): Update it.
(qtgraphicaleffects): Update it.

gnu: qtkeychain: Use modular qt.

* gnu/packages/qt.scm (qtkeychain)[inputs]: Add qtbase. Remove qt.
  [native-inputs]: Add qttools.

gnu: poppler-qt5: Use modular qt.

* gnu/packages/pdf.scm (poppler-qt)[inputs]: Add qtbase. Remove qt.

gnu: gst-plugins-bad: Use modular qt.

* gnu/packages/gstreamer.scm (gst-plugins-bad)[inputs]: Add qtbase. Remove qt.

gnu: bitcoin-core: Use modular qt.

* gnu/packages/finance.scm (bitcoin-core)[inputs]: Add qtbase. Remove qt.

gnu: fritzing: Use modular qt.

* gnu/packages/engineering.scm (fritzing)[inputs]: Add qtbase, qtserialport,
qtsvg. Remove qt.

gnu: qsynth: Use modular qt.

* gnu/packages/audio.scm (qsynth)[inputs]: Add qtbase, qtx11extras. Remove qt.
[native-inputs]: Add qttools.

gnu: polkit-qt: Use modular qt.

* gnu/packages/polkit.scm (polkit-qt)[propagated-inputs]: Add qtbase. Remove qt.

gnu: kwidgetsaddons: Fix test failure.

* gnu/packages/kde-frameworks.scm (kwidgetsaddons)[arguments]:
Enable tests. Set Xvfb pixel depth to 24 bits.

gnu: modemmanager-qt: Propagate modem-manager.

* gnu/packages/kde-frameworks.scm (modemmanager-qt)
[propagated-inputs]: Add modem-manager.
[inputs]: Remove modem-manager.

gnu: networkmanager-qt: Propagate network-manager.

* gnu/packages/kde-frameworks.scm (networkmanager-qt)
[propagated-inputs]: Add network-manager.
[inputs]: Remove network-manager.

gnu: Add wayland-protocols.

* gnu/packages/freedesktop.scm (wayland-protocols): New variable.

gnu: Add mobile-broadband-provider-info.

* gnu/packages/gnome.scm (mobile-broadband-provider-info): New variable.

gnu: Add lndir.

* gnu/packages/xorg.scm (lndir): New variable.

gnu: Add snappy.

* gnu/packages/compression.scm (snappy): New variable.

Co-authored-by: Alex Kost <alezost@gmail.com>

gnu: Add jsoncpp.

* gnu/packages/serialization.scm (jsoncpp): New variable.

gnu: Add yaml-cpp.

* gnu/packages/serialization.scm (yaml-cpp): New variable.