Add API to get full list of stacks for an item/fluid type.

[uecasm]

This adds an API method to allow fetching the complete list of stacks matching a given item type.

(The existing APIs only let you get a list of all stacks of all types [which is less efficient], or the first stack matching a given item/fluid name and NBT matching flags [which may be insufficient].)

The motivating case is to allow a more complex NBT comparison for an item by calling the new getStacks(type) (which is more efficient than calling getStacks() as it doesn't need to process many extraneous items on large storages), perform some custom logic to decide which of these stacks is the one desired (e.g. by evaluating the tags), and then use that stack in further operations (such as extracting it).

I considered an alternative implementation that returned only the ItemStack/FluidStack in the list rather than the full entry, but (a) providing the UUID might enable using get(uuid) to try a faster lookup later on, and (b) this way seemed more efficient since it doesn't require creating a new collection.