Introduced the MasterController as part of working on loading catalogue information.

Need a central piece to manage the catalogue data per database to prevent loading
this multiple times. MasterController is now also used to enable reopening the
connection manager from a query window after the connection manager has been closed.

connectionconfig.cpp

@@ -200,3 +200,13 @@ const char * const * ConnectionConfig::getValues() const
 
 	return m_values.data();
 }
+
+bool ConnectionConfig::isSameDatabase(const ConnectionConfig &rhs) const
+{
+	return m_host     == rhs.m_host
+		&& m_hostaddr == rhs.m_hostaddr
+		&& m_port     == rhs.m_port
+		&& m_user     == rhs.m_user
+		&& m_password == rhs.m_password
+		&& m_dbname   == rhs.m_dbname;
+}