refactor: adding function to check if server config file have the needed read permissions

src/lib/common/Settings.cpp

@@ -238,6 +238,12 @@ QString Settings::serverConfigFile()
   return useExt ? value(Server::ExternalConfigFile).toString() : defaultValue(Server::ExternalConfigFile).toString();
 }
 
+bool Settings::isServerConfigFileReadable()
+{
+  auto file = QFile(serverConfigFile());
+  return file.open(QFile::ReadOnly);
+}
+
 bool Settings::isWritable()
 {
   return instance()->m_settings->isWritable();

src/lib/common/Settings.h

@@ -130,6 +130,7 @@ public:
   static QVariant value(const QString &key = QString());
   static void restoreDefaultSettings();
   static QVariant defaultValue(const QString &key);
+  static bool isServerConfigFileReadable();
   static bool isWritable();
   static bool isPortableMode();
   static QString settingsFile();