Add random_str helper function

[tdotfish]

What is the problem you are trying to solve?

Would like to generate random integers (or perhaps strings of numbers) similar to the random_str() function.

How are you currently being hindered by this problem?

There are some cases where I may want to send random number instead of a random string, for example on an insertion point that only accepts numbers and rejects any non-numeric characters.

How would you like this problem to be solved?

No preference.

Any additional details?