Add save and restore of each pin used in reading joystick (AVR).

Allow output pin to be JS_VIRTUAL_AXIS if the axis is connected to Vcc
instead of an output pin from the MCU.

Fix joystick report id

Fix broken v-usb hid joystick interface. Make it more resilient to unusual settings (none multiple of eight button count, 0 buttons or 0 axes)

Correct adc reading for multiple axes. Piecewise range conversion for uncentered raw value range. Input, output and ground pin configuration per axis.

Documentation fixes

quantum/process_keycode/process_joystick.h

@@ -8,6 +8,7 @@ bool process_joystick(uint16_t keycode, keyrecord_t *record);
 
 void joystick_task(void);
 
-bool process_joystick_analog(void);
+bool process_joystick_analogread(void);
+bool process_joystick_analogread_quantum(void);
 
 #endif //PROCESS_JOYSTICK_H