added java code for N-Queen (LEETCODE - HARD)

[Yuktikashyap]

Heyy @fineanmol this is a very famous Leetcdoe HARD Level problem - N-Queens
link - https://leetcode.com/problems/n-queens
I will be solving this problem using Recursion
Kindly assign this to be as a part of Hactoberfest2023.I will be solving this in JAVA language.
Thanks

[github-actions]

@Yuktikashyap Please Star ⭐️ the repo to earn "hacktober-accepted" label for the event.
Meanwhile if you want to work on this issue, Please raise the PR and we will review and merge it.

[Yuktikashyap]

Heyy @fineanmol this is a very famous Leetcdoe HARD Level problem - N-Queens
link - https://leetcode.com/problems/n-queens
I will be solving this problem using Recursion
Kindly assign this to be as a part of Hactoberfest2023.I will be solving this in JAVA language.
Thanks