Streamlined searcher code

* Remove searching of group title and notes
* End search when selecting a new group
* Correct entry searcher tests to align with new code

src/gui/DatabaseWidget.h

@@ -138,7 +138,7 @@ signals:
     void mainSplitterSizesChanged();
     void previewSplitterSizesChanged();
     void entryViewStateChanged();
-    void updateSearch(QString text);
+    void clearSearch();
 
 public slots:
     void createEntry();