[Dana] Add rotatefun program

[nspyrop03]

Added rotatefun.dana program.
This program solves the fun leetcode problem 396. Rotate Function.

Input:

1. n: number of integers the user will give
2. n integers stored in int array called nums

Output:

1. the result of the problem followed by a new line character

[kostis]

Thanks for your contribution.

It would be better if this PR gets extended with a set of rotatefun.input and rotatefun.result files containing a sample input and expected result. (Look also in e.g. the alan/programs dir where similar files exist for many programs.)

Then I will merge this.

[nspyrop03]

I've pushed the set of files for input and expected output.