removed unnecessary plugin node wrapper

Removed PluginNodeHashWrapper and moved equals and hashCode logic into PluginNode

scm-webapp/src/main/java/sonia/scm/plugin/PluginNode.java

@@ -175,6 +175,17 @@ public final class PluginNode
     this.wrapper = wrapper;
   }
 
+  @Override
+  public int hashCode() {
+    return getId().hashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    return obj instanceof PluginNode
+      && ((PluginNode) obj).getId().equals(this.getId());
+  }
+
   @Override
   public String toString() {
     return plugin.getPath().toString() + " -> " + children;