Dont recreate stackables every move

[nekiro]

Pull Request Prelude

• I have followed proper The Forgotten Server code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

Don't recreate stackables on every move, create new stackables only when splitting the stack.

Issues addressed:
Stackable items are recreated even when they shouldn't, if you move a full stack of stackable item, why would you create a new item and delete the old one?
This seems pretty wasteful and unnecessary.

[ranisalt]

Assuming the new count can never be negative, how about this?

Suggested change

	if (newCount == item->getItemCount()) {
	// full item is moved (move count is the same as item count)
	} else if (newCount > 0) {
	moveItem = item->clone();
	moveItem->setItemCount(newCount);
	} else {
	if (item->isRemoved()) {
	ReleaseItem(item);
	}
	moveItem = nullptr;
	}
	assert(newCount >= 0);
	if (newCount != item->getItemCount()) {
	moveItem = item->clone();
	moveItem->setItemCount(newCount);
	} else if (newCount == 0) {
	if (item->isRemoved()) {
	ReleaseItem(item);
	}
	moveItem = nullptr;
	}

[ranisalt]

Attention: the code above may cause duplication bugs that I couldn't trace. Please don't apply it without testing beforehand.