Add memoization utility snippet

[iluwatar]

Description:

Implement a memoization utility that caches results of a function to avoid repeated computation. The snippet should use a Map to store input/output pairs.

The snippet should accept a Function<T, R> and return a memoized version of the same function. Internally, it should use a thread-safe cache (e.g., ConcurrentHashMap) to store the input/output mapping.

This utility is particularly useful in functional programming contexts, or when building services that rely on frequently repeated expensive computations.

Acceptance Criteria:

• A new memoization snippet has been added
• Method Function<T, R> memoize(Function<T, R>) is provided.
• Demonstrate/test usage with a recursive Fibonacci function.
• Cache is used to optimize repeated calls.