Add new functions to the js interpreter: random, analogWrite, digitalRead, analogRead

[Tawank]

Proposed Changes

• Added new functions to the JavaScript interpreter: random, analogWrite, digitalRead, analogRead.
• Added new global variables to the JavaScript interpreter: HIGH, LOW, INPUT, OUTPUT, PULLUP, etc.
• Modified the gpio mode serial command to accept values between 0 and 9.

In the documentation there is an error in this fragment:
https://github.com/pr3y/Bruce/wiki/Serial
gpio mode <pin number> <0/1> - set GPIO pins mode (0=input, 1=output).

While this is true for Arduino boards, it is not accurate for ESP32:
https://github.com/espressif/arduino-esp32/blob/master/cores/esp32/esp32-hal-gpio.h#L46
Here, 1 is for input, while 2 and 3 is for output.

I've updated documentation according to this, and also added new functions:
https://github.com/Tawank/Bruce-wiki/pull/1/files

I've also added the gobal variables INPUT, OUTPUT, HIGH, LOW, so you can initialize pin like this in the js script:
pinMode(25, OUTPUT);

Types of Changes

Bugfix, New Feature

Verification

I wired up potentiometer and tested the analogRead command on pins 25 and 26.
And tested analogWrite, digitalRead and random commands.

User-Facing Change

- Added new functions to the JavaScript interpreter: random, analogWrite, digitalRead, analogRead.
- Added new global variables to the JavaScript interpreter: HIGH, LOW, INPUT, OUTPUT, PULLUP, etc.