Breakage caused by PinStatus and PinMode types

This project changes `LOW`, `HIGH`, `INPUT`, `INPUT_PULLUP`, and `OUTPUT` from macros to enums:
https://github.com/arduino/ArduinoCore-API/blob/e1eb8de126786b7701b211332dda3f09aa400f35/api/Common.h#L10-L23

I'm concerned that this will cause breakage of a significant amount of existing code.

An example is the popular [Keypad library](https://playground.arduino.cc/code/keypad). Compilation of both the [original](https://playground.arduino.cc/uploads/Code/keypad.zip) library and the [version in Library Manager](https://github.com/Chris--A/Keypad) fails once this change is made.
```
In file included from E:\electronics\arduino\libraries\Keypad-master\examples\HelloKeypad\HelloKeypad.ino:10:0:

E:\electronics\arduino\libraries\Keypad-master\src/Keypad.h: In member function 'virtual void Keypad::pin_write(byte, boolean)':

E:\electronics\arduino\libraries\Keypad-master\src/Keypad.h:81:81: error: cannot convert 'boolean {aka bool}' to 'PinStatus' for argument '2' to 'void digitalWrite(pin_size_t, PinStatus)'

virtual void pin_write(byte pinNum, boolean level) { digitalWrite(pinNum, level); }
```
This commonly used code will also now fail:
```c++
digitalWrite(13, !digitalRead(13)); // toggle pin 13
```
```
toggle:2:36: error: cannot convert 'bool' to 'PinStatus' for argument '2' to 'void digitalWrite(pin_size_t, PinStatus)'

digitalWrite(13, !digitalRead(13)); // toggle pin 13
```
I understand that the root cause of these errors is bad code and that any code which followed best practices will have no problems with this change. However, I fear there is a lot of bad code in widespread use that currently works fine. In the case of the Keypad library, it is unlikely it can even be fixed since Chris--A has gone AWOL. I'm sure there are other such abandoned projects.

I do like the spirit of this change (though lumping `CHANGE`, `FALLING`, and `RISING` into `PinStatus` is questionable). I'm open to being convinced that it's worth the breakage and, if so, I'm willing to help ease the transition by providing user support and submitting PRs to fix broken code. I just think this warrants some consideration before ArduinoCore-API goes into more widespread use.

### Additional context

Some previous discussion on the topic:

- http://forum.arduino.cc/index.php?topic=455579 (from [here](http://forum.arduino.cc/index.php?topic=455579.msg4001965#msg4001965) onward)
- https://forum.arduino.cc/index.php?topic=584322
- http://forum.arduino.cc/index.php?topic=602250
- https://forum.arduino.cc/index.php?topic=621429
- https://forum.arduino.cc/index.php?topic=627883.msg4319254#msg4319254
- https://forum.arduino.cc/index.php?topic=659624
- https://github.com/arduino/ArduinoCore-megaavr/issues/68

#### Related

- https://github.com/arduino/ArduinoCore-mbed/issues/1107

Bắt đầu với api/Common.h và tái hiện các lỗi biên dịch đã được báo cáo bằng các ví dụ Keypad và trường hợp digitalWrite(13, !digitalRead(13)). Xem lại các cuộc thảo luận được liên kết và issue liên quan để hiểu quyết định về khả năng tương thích; issue này chỉ hoàn tất khi dự án đưa ra và ghi lại một quyết định, đồng thời hành vi tương thích bị ảnh hưởng đã được xác minh.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.