ui: moved recent projects submenu

* moved the menu entry for "recent projects" to be placed close to "open project"
* replaced enum for MaxRecentProjectsCount in AppSettings by a getter function.

src/lib/settings/ApplicationSettings.h

@@ -14,10 +14,7 @@ public:
 
 	std::string getStartupProjectFilePath() const;
 
-	enum
-	{
-		MaximalAmountOfRecentProjects = 7
-	};
+	int getMaxRecentProjectsCount() const;
 
 	// source
 	std::vector<FilePath> getHeaderSearchPaths() const;