Create ThreeFiveMultiples.js

Have the function ThreeFiveMultiples(num) return the sum of all the multiples of 3 and 5 that are below num. For example: if num is 10, the multiples of 3 and 5 that are below 10 are 3, 5, 6, and 9, and adding them up you get 23, so your program should return 23. The integer being passed will be between 1 and 100.