Add Method to add PackURL Without In-Memory Download of Resource Pack

[EinBexiii]

Description

The current implementation, as seen in the method at pack.go, stores the pack in the server's memory, which can be problematic for servers with restricted memory capacity, particularly on devices with RAM limitations such as Android.

Problem

Servers with limited RAM are at risk of crashing when handling large resource packs (100MB+), as the current method reads all bytes into memory.

Proposed Solution

To circumvent this limitation, I propose the addition of a new method that allows to provide only the PackURL and validating without downloading the pack. This new method should:

• Validate the provided PackURL to ensure it's a valid and reachable URL.