Refactor the console subsystem

Rename cli.ino => console.ino.
Rename handleInput => handleConsole.
Separate console initialization function.
Always use usb cdc by default on s3/c3 (no configuration needed).

gazebo/flix.h

@@ -45,7 +45,7 @@ void testMotor(int, float);
 void print(const char* format, ...);
 void pause(float duration);
 void doCommand(String str, bool echo);
-void handleInput();
+void handleConsole();
 void setupRC();
 void normalizeRC();
 void calibrateRC();