Doc: Add docs for SimpleKeyboard example

Fixes: QDS-4140
Change-Id: Icf1da91512848881914ac4c44e47ecc6e5bc3903
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

doc/qtdesignstudio/examples/SimpleKeyboard/SimpleKeyboard.qmlproject

@@ -0,0 +1,45 @@
+import QmlProject 1.1
+
+Project {
+    mainFile: "SimpleKeyboard.qml"
+
+    /* Include .qml, .js, and image files from current directory and subdirectories */
+    QmlFiles {
+        directory: "."
+    }
+
+    JavaScriptFiles {
+        directory: "."
+    }
+
+    ImageFiles {
+        directory: "."
+    }
+
+    Files {
+        filter: "*.conf"
+        files: ["qtquickcontrols2.conf"]
+    }
+
+    Files {
+        filter: "qmldir"
+        directory: "."
+    }
+
+    Files {
+        filter: "*.ttf;*.otf"
+    }
+
+    Environment {
+        QT_QUICK_CONTROLS_CONF: "qtquickcontrols2.conf"
+        QT_AUTO_SCREEN_SCALE_FACTOR: "1"
+        QT_IM_MODULE: "qtvirtualkeyboard"
+        QT_VIRTUALKEYBOARD_DESKTOP_DISABLE: 1
+    }
+
+    /* List of plugin directories passed to QML runtime */
+    importPaths: [ "imports", "asset_imports" ]
+
+    /* Required for deployment */
+    targetDirectory: "/opt/SimpleKeyboard"
+}