Expose effect ID to scripting via effect.pluginId

This can be used to avoid code duplication by installing an effect multiple
times and tweaking behavior slightly based on the returned ID.

Internally it is called `scriptName` but for consistency with other similar
APIs the name `pluginId` is chosen, and returns e.g. `kwin4_effect_maximize`

scripting/scriptedeffect.cpp

@@ -694,6 +694,11 @@ void ScriptedEffect::animationEnded(KWin::EffectWindow *w, Attribute a, uint met
     emit animationEnded(w, 0);
 }
 
+QString ScriptedEffect::pluginId() const
+{
+    return m_effectName;
+}
+
 bool ScriptedEffect::isActiveFullScreenEffect() const
 {
     return effects->activeFullScreenEffect() == this;

scripting/scriptedeffect.h

@@ -28,6 +28,10 @@ class KWIN_EXPORT ScriptedEffect : public KWin::AnimationEffect
     Q_ENUMS(MetaType)
     Q_ENUMS(EasingCurve)
     Q_ENUMS(SessionState)
+    /**
+     * The plugin ID of the effect
+     */
+    Q_PROPERTY(QString pluginId READ pluginId CONSTANT)
     /**
      * True if we are the active fullscreen effect
      */
@@ -108,6 +112,8 @@ public:
         return m_screenEdgeCallbacks;
     }
 
+    QString pluginId() const;
+
     bool isActiveFullScreenEffect() const;
 
     bool registerTouchScreenCallback(int edge, QScriptValue callback);