Add ability to change the behavior of our converter to number

[andrewtelnov]

Add a callback function to override the default behavior:

//newValue could be NaN if it could not convert the value
parseNumber: (originalValue: any, newValue: number): number => newValue,

The following code should be write to convert the following strings to number: "123,0134,993". The default converter will return NaN for these strings:

import { settings, Helpers } from "survey-core";

settings.parseNumber = (originValue, numberValue) => {
    if(typeof originValue !== "string" || !originValue) return numberValue;
    if(originValue.indexOf(",") < 0) return numberValue;
    while(originValue.indexOf(",") > -1) {
      originValue = originValue.replace(",", "");
    }
    return Helpers.getNumber(originValue);
  };