gui: add accessibility hints to connection button

this added metadata is used by accessibility tools for
aiding the user to interact with the application

gui/components/StatusBox.qml

@@ -146,6 +146,8 @@ Item {
             Layout.alignment: Qt.AlignBottom
             padding: 0
             display: AbstractButton.IconOnly
+            Accessible.name: qsTr("Turn on")
+            Accessible.role: Accessible.Button
             HoverHandler {
                 cursorShape: Qt.PointingHandCursor
             }

gui/components/VPNState.qml

@@ -95,6 +95,7 @@ StateGroup {
                 target: toggleVPN
                 enabled: true
                 icon.source: Theme.buttonDisconnected
+                Accessible.name: qsTr("Turn on")
             }
             PropertyChanges {
                 target: systray
@@ -130,6 +131,7 @@ StateGroup {
                 target: toggleVPN
                 enabled: true
                 icon.source: Theme.buttonConnected
+                Accessible.name: qsTr("Turn off")
             }
             PropertyChanges {
                 target: systray
@@ -167,6 +169,7 @@ StateGroup {
                 target: toggleVPN
                 enabled: true
                 icon.source: Theme.buttonConnecting
+                Accessible.name: qsTr("Cancel")
             }
             PropertyChanges {
                 target: systray
@@ -205,6 +208,7 @@ StateGroup {
             PropertyChanges {
                 target: toggleVPN
                 icon.source: Theme.buttonConnecting
+                Accessible.name: qsTr("Cancel")
             }
             PropertyChanges {
                 target: systray