Added arrayCumSum Function

Why it matters

This feature introduces a new function that calculates the cumulative sum of elements within an array. It helps users efficiently perform cumulative sum operations directly on array data structures, simplifying query logic and improving performance when working with arrays.

How to use it

Use the function by passing an array column or array expression to arrayCumSum in your SQL queries. For example:

SELECT arrayCumSum(array_column) FROM table

This will return an array where each element is the cumulative sum up to that position.