Add Java Program to find all the permutations of a string

[AbhinavRajputEXE]

Is your feature request related to a problem? Please describe.
I would like to make a java program to find all the permutations of a string

Describe the solution you'd like
We can solve this problem by using a backtracking algorithm.

Additional context
Image to understand the algorithm.

[AbhinavRajputEXE]

@siriak Please assign this issue to me.