otto_servo.js for esp8266 & esp32

[sfranzyshen]

https://www.espruino.com/Servo+Motors
https://www.espruino.com/PWM
https://www.espruino.com/modules/servo.js

[sfranzyshen]

first otto_servo.js attempt is up and functional ... again it's modeled after the esp8266 arduino servo driver but only what is required by the OttoDIY API ... I used analogWrite() instead of digitalPulse() ... this is how the original arduino Servo code operates and inline with how the python port works too ...