Build demo examples directory

The directory will host more demos in the future so it is
wise to enable CI to build it and report issues, if any.

Change-Id: I97fbe8fc7589ec2c18e1dcb32c02a40332f9453b
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

examples/demos/coffee/coffee.pro

@@ -23,9 +23,8 @@ DEFINES += QT_DEPRECATED_WARNINGS
 # You can also select to disable deprecated APIs only up to a certain version of Qt.
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
 
-# Default rules for deployment.
 qnx: target.path = /tmp/$${TARGET}/bin
-else: unix:!android: target.path = /opt/$${TARGET}/bin
+else: win32|if(unix:!android): target.path = $$[QT_INSTALL_EXAMPLES]/demos/$${TARGET}
 !isEmpty(target.path): INSTALLS += target
 
 DISTFILES += \

examples/demos/demos.pro

+TEMPLATE = subdirs
+
+qtHaveModule(quick) {
+    SUBDIRS += coffee
+}
+

examples/examples.pro

+TEMPLATE = subdirs
+
+SUBDIRS = demos
+

qtdoc.pro

-TEMPLATE = subdirs
-SUBDIRS = doc
+load(qt_parts)
+
+SUBDIRS += doc