Added tab navigation functional. (#721)

- Added tab navigation functional.
- In basic types added parentFlickable property, which will help to ensure, that the item is visible within flickable parent during tab navigation.
- Added focus state for some basic types.
- In PageType qml file added lastItemTabClicked function, which will help to focus tab bar buttons when the last tab on the current page clicked.
- Added Focus for back button for all pages and drawers.
- Added scroll on tab for Servers ListView on PageHome.

client/ui/qml/Components/HomeSplitTunnelingDrawer.qml

@@ -24,6 +24,14 @@ DrawerType2 {
         anchors.right: parent.right
         spacing: 0
 
+        Connections {
+            target: root
+            enabled: !GC.isMobile()
+            function onOpened() {
+                focusItem.forceActiveFocus()
+            }
+        }
+
         Header2Type {
             Layout.fillWidth: true
             Layout.topMargin: 24
@@ -35,7 +43,13 @@ DrawerType2 {
             descriptionText:  qsTr("Allows you to connect to some sites or applications through a VPN connection and bypass others")
         }
 
+        Item {
+            id: focusItem
+            KeyNavigation.tab: splitTunnelingSwitch.visible ? splitTunnelingSwitch : siteBasedSplitTunnelingSwitch.rightButton
+        }
+
         LabelWithButtonType {
+            id: splitTunnelingSwitch
             Layout.fillWidth: true
             Layout.topMargin: 16
 
@@ -45,6 +59,8 @@ DrawerType2 {
             descriptionText: qsTr("Enabled \nCan't be disabled for current server")
             rightImageSource: "qrc:/images/controls/chevron-right.svg"
 
+            KeyNavigation.tab: siteBasedSplitTunnelingSwitch.visible ? siteBasedSplitTunnelingSwitch.rightButton : focusItem
+
             clickedFunction: function() {
 //                PageController.goToPage(PageEnum.PageSettingsSplitTunneling)
 //                root.close()
@@ -56,6 +72,7 @@ DrawerType2 {
         }
 
         LabelWithButtonType {
+            id: siteBasedSplitTunnelingSwitch
             Layout.fillWidth: true
             Layout.topMargin: 16
 
@@ -63,6 +80,10 @@ DrawerType2 {
             descriptionText: enabled && SitesModel.isTunnelingEnabled ? qsTr("Enabled") : qsTr("Disabled")
             rightImageSource: "qrc:/images/controls/chevron-right.svg"
 
+            KeyNavigation.tab: appSplitTunnelingSwitch.visible ?
+                                   appSplitTunnelingSwitch.rightButton :
+                                   focusItem
+
             clickedFunction: function() {
                 PageController.goToPage(PageEnum.PageSettingsSplitTunneling)
                 root.close()
@@ -73,6 +94,7 @@ DrawerType2 {
         }
 
         LabelWithButtonType {
+            id: appSplitTunnelingSwitch
             visible: isAppSplitTinnelingEnabled
 
             Layout.fillWidth: true
@@ -81,6 +103,8 @@ DrawerType2 {
             descriptionText: AppSplitTunnelingModel.isTunnelingEnabled ? qsTr("Enabled") : qsTr("Disabled")
             rightImageSource: "qrc:/images/controls/chevron-right.svg"
 
+            KeyNavigation.tab: focusItem
+
             clickedFunction: function() {
                 PageController.goToPage(PageEnum.PageSettingsAppSplitTunneling)
                 root.close()