TFTP

Change to my own struct for the virtual files
init the index.txt from the tftp_server_init
add tftp_server_deinit + add to docs

docs/tftp.md

@@ -6,6 +6,13 @@ The TFTP task is initialized in the main function.
 // Initialize TFTP task
 tftp_init();
 ```
+## Deinitialization
+If you would ever want to deinitialize the TFTP task, you can do so by calling the following function.
+```c
+// Deinitialize TFTP task
+tftp_server_deinit();
+```
+
 ## Usage
 The TFTP task is used to receive and send files via TFTP.
 ### Receive a file