[branding] add Manjaro branding

src/branding/manjaro-kde/branding.desc

src/branding/manjaro-kde/languages.png

src/branding/manjaro-kde/logo.png

src/branding/manjaro-kde/show.qml

src/branding/manjaro-kde/slide1.png

src/branding/manjaro-kde/slide2.png

src/branding/manjaro-kde/slide3.png

src/branding/manjaro-kde/slide4.png

src/branding/manjaro-kde/slide5.png

src/branding/manjaro-kde/squid.png

src/branding/manjaro-xfce/branding.desc

src/branding/manjaro-xfce/languages.png

src/branding/manjaro-xfce/logo.png

src/branding/manjaro-xfce/show.qml

src/branding/manjaro-xfce/slide1.png

src/branding/manjaro-xfce/slide2.png

src/branding/manjaro-xfce/slide3.png

src/branding/manjaro-xfce/slide4.png

src/branding/manjaro-xfce/slide5.png

src/branding/manjaro-xfce/squid.png