Refactor alarm system and replace notification method

The old OpenVR overlays did not function for unknown reasons, and it was
not possible to get them to work.

With this a white overlay with ALARM ACTIVATED will be shown for 3 seconds.
It's not pretty, but it effectively communicates that an alarm has been
activated.

This fixes
https://github.com/OpenVR-Advanced-Settings/OpenVR-AdvancedSettings/issues/417

src/res/qml/common/HourComboBox.qml

@@ -0,0 +1,50 @@
+import QtQuick 2.7
+import QtQuick.Controls 2.0
+import QtQuick.Layouts 1.3
+import ovras.advsettings 1.0
+
+MyComboBox {
+    textRole: "text"
+    valueRole: "value"
+    model: [
+        { value: 0, text: "00" },
+        { value: 1, text: "01" },
+        { value: 2, text: "02" },
+        { value: 3, text: "03" },
+        { value: 4, text: "04" },
+        { value: 5, text: "05" },
+        { value: 6, text: "06" },
+        { value: 7, text: "07" },
+        { value: 8, text: "08" },
+        { value: 9, text: "09" },
+        { value: 10, text: "10" },
+        { value: 11, text: "11" },
+        { value: 12, text: "12" },
+        { value: 13, text: "13" },
+        { value: 14, text: "14" },
+        { value: 15, text: "15" },
+        { value: 16, text: "16" },
+        { value: 17, text: "17" },
+        { value: 18, text: "18" },
+        { value: 19, text: "19" },
+        { value: 20, text: "20" },
+        { value: 21, text: "21" },
+        { value: 22, text: "22" },
+        { value: 23, text: "23" },
+    ]
+
+    delegate: ItemDelegate {
+        width: parent.width
+        text: modelData.text
+        hoverEnabled: true
+        contentItem: MyText {
+            horizontalAlignment: Text.AlignLeft
+            verticalAlignment: Text.AlignVCenter
+            text: parent.text
+            color: parent.enabled ? "#ffffff" : "#909090"
+        }
+        background: Rectangle {
+            color: parent.pressed ? "#406288" : (parent.hovered ? "#365473" : "#2c435d")
+        }
+    }
+}