added frontend minor readme

groundStation/src/frontend/Readme.md.txt

+Frontend Explained
+==================
+
+The frontend is what handles clients. It manages a connection to the backend over
+a tcp socket. It features a number of possible commands which can be sent to the backend.
+The GUI and CLI are both clients that call functions on the frontend directly in order to
+communicate with the backend.
+
+See the groundstation readme for more information about possible commands.
\ No newline at end of file