centralize and fixup example sources install targets

This follows suit with aeb036e in qtbase.

Change-Id: Ie8580d0a1f38ab9858b0e44c9f99bdc552a1752a
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: hjk <qthjk@ovi.com>

examples/multimediawidgets/camera/camera.pro

@@ -0,0 +1,25 @@
+TEMPLATE = app
+TARGET = camera
+
+QT += multimedia multimediawidgets
+
+HEADERS = \
+    camera.h \
+    imagesettings.h \
+    videosettings.h
+
+SOURCES = \
+    main.cpp \
+    camera.cpp \
+    imagesettings.cpp \
+    videosettings.cpp
+
+FORMS += \
+    camera.ui \
+    videosettings.ui \
+    imagesettings.ui
+
+target.path = $$[QT_INSTALL_EXAMPLES]/multimediawidgets/camera
+INSTALLS += target
+
+QT+=widgets