iOS build: add various support files

It's unclear why the build fails if we don't add the sample app files as
well.

[Dirk Hohndel: refactored the patches]

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

packaging/ios/subsurface-ios/MainForm.ui.qml

@@ -0,0 +1,25 @@
+import QtQuick 2.6
+import QtQuick.Controls 1.5
+import QtQuick.Layouts 1.3
+
+Item {
+    width: 640
+    height: 480
+
+    property alias button1: button1
+    property alias button2: button2
+
+    RowLayout {
+        anchors.centerIn: parent
+
+        Button {
+            id: button1
+            text: qsTr("Press Me 1")
+        }
+
+        Button {
+            id: button2
+            text: qsTr("Press Me 2")
+        }
+    }
+}