reorganize code and added documentation

software/pc_client/src/serial/ftdi485.h

@@ -0,0 +1,23 @@
+/*
+ * This file is part of the split-flap project.
+ * Copyright (c) 2024-2025 GuniaLabs (www.dennisgunia.de)
+ * Authors: Dennis Gunia
+ *
+ * This program is licenced under AGPL-3.0 license.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <fcntl.h> // Contains file controls like O_RDWR
+#include <errno.h> // Error integer and strerror() function
+#include <string.h>
+#include <termios.h> // Contains POSIX terminal control definitions
+#include <unistd.h>  // write(), read(), close()
+#include <sys/types.h>
+
+#define RS485TX 0
+#define RS485RX 1
+
+int rs485_init(char *device, int baud);