refactor: split formatters and matchers into separated singleton classes (#166)

* split formatter into separated singleton classes

* split data engine matchers to classes

* nodiscard attribute for formatter methods

* small refactoring in matchers

* fix codefactor warnings

* fix test building

sources/awesome-widget/plugin/awpairconfigfactory.h

@@ -29,6 +29,4 @@ public:
     ~AWPairConfigFactory() override = default;
     Q_INVOKABLE static void showFormatterDialog(const QStringList &_keys);
     Q_INVOKABLE static void showKeysDialog(const QStringList &_keys);
-
-private:
 };