Added Array Manipulation Functions

Why it matters

These functions address the need for more comprehensive and convenient ways to manipulate arrays within ClickHouse queries. They simplify array operations, improve query expressiveness, and enhance performance by providing native support for common array tasks such as joining arrays, extracting subarrays, and modifying arrays by adding or removing elements at either end.

How to use it

Use the new functions in SQL queries to manipulate arrays:

- concat(array1, array2, ...) — concatenates multiple arrays into one.
- arraySlice(array, start, [length]) — extracts a slice of the array starting at start index, optionally with a specified length.
- arrayPushBack(array, element) — adds an element at the end of the array.
- arrayPushFront(array, element) — adds an element at the beginning of the array.
- arrayPopBack(array) — removes the last element from the array.
- arrayPopFront(array) — removes the first element from the array.

Example:

SELECT concat([1, 2], [3, 4]) AS result;
SELECT arraySlice([1, 2, 3, 4], 2, 2) AS result;