feat: context menu for Keyboard Layout applet

Counterpart commit with the same title is in P-D

components/keyboardlayout/keyboardlayout.cpp

@@ -68,6 +68,11 @@ void KeyboardLayout::switchToPreviousLayout()
     if (mIface) mIface->switchToPreviousLayout();
 }
 
+void KeyboardLayout::setLayout(const QString &layout)
+{
+    if (mIface) mIface->setLayout(layout);
+}
+
 template<class T>
 void KeyboardLayout::requestDBusData(QDBusPendingReply<T> pendingReply, T &out, void (KeyboardLayout::*notify)())
 {

components/keyboardlayout/keyboardlayout.h

@@ -18,6 +18,9 @@ class KeyboardLayout : public QObject
 {
     Q_OBJECT
 
+    Q_PROPERTY(QString layout
+               WRITE setLayout)
+
     Q_PROPERTY(QString layoutDisplayName
                MEMBER mLayoutDisplayName
                NOTIFY layoutDisplayNameChanged)
@@ -44,6 +47,8 @@ protected Q_SLOTS:
     void switchToPreviousLayout();
 
 private:
+    void setLayout(const QString &layout);
+
     enum DBusData {LayoutDisplayName, LayoutLongName, Layouts};
 
     template<class T>

components/workspace/KeyboardLayoutButton.qml

@@ -11,11 +11,10 @@ import org.kde.plasma.workspace.keyboardlayout 1.0
 PlasmaComponents3.ToolButton {
     id: kbLayoutButton
 
-    property alias layoutShortName: layout.layoutDisplayName
-    property alias layoutLongName: layout.layoutLongName
+    property alias layout: layout
     readonly property bool hasMultipleKeyboardLayouts: layout.layouts.length > 1
 
-    text: layoutLongName
+    text: layout.layoutLongName
     visible: hasMultipleKeyboardLayouts
 
     Accessible.name: i18ndc("plasma_lookandfeel_org.kde.lookandfeel", "Button to change keyboard layout", "Switch layout")