static excel2coord(str) {
    const l = str.length;
    let index = 0;
    let alpha = '';
    let numeric = '';
    while (index < l && XTableUtils.isAlphaChar(str[index])) {
      alpha += str[index];
      index += 1;
    }
    while (index < l) {
      numeric += str[index];
      index += 1;
    }
    return {
      column: XTableUtils.alpha2number(alpha),
      row: Number.parseInt(numeric, 10) - 1,
    };
  }
Given an excel coordinate (example: 'BC123') transform it
to decimal coordinates.
@param {String} str Excel coordinate.
@returns {Object} Coordinate in format { column: ..., row: ...}