Added StackUtils.java - This utility provides commonly used operations related to stacks

[mohit-gogitter]

Here's a stack-based utility in Java that can be used by other developers in their solutions.
This utility provides commonly used operations related to stacks, which can be beneficial for solving various problems such as expression evaluations, balanced parentheses, or maintaining a history of operations.

Utility: Custom Stack Utility
This utility will include the following stack-related operations:

MinStack: A stack that supports retrieving the minimum element in constant time. This custom stack keeps track of the minimum element so that getMin() can return the minimum in O(1) time.

Next Greater Element: Given an array, find the next greater element for each element in the array. For each element in an array, the utility finds the next greater element on the right side using a stack.

Balanced Parentheses Checker: A utility to check whether a given expression has balanced parentheses. It checks if an expression has matching and balanced parentheses.

Reverse a Stack: Function to reverse a stack.

[mohit-gogitter]

closing as I have implemented this in C#