Rework the /origin command

[eggohito]

This PR refactors the old code for the pre-existing sub-commands of the /origin command. It also adds a new sub-command, random with <targets> <layer> as its arguments; it randomizes the origin of the specified target(s) in the specified origin layer.

e.g:

#  Randomize the origin of the current player in the `origins:origin` origin layer:
origin random @s origins:origin


#  You can also randomize the origin of certain players in other origin layers, like so:
origin random @a[sort = random, limit = 3] origins-classes:class

origin random @a[tag = test] origins:origin

origin random @a example:custom_layer

[eggohito]

Converting the PR as draft for now since I haven't tested it extensively yet

[eggohito]

This PR should also fix some issues regarding the origin and origin layer argument types.
(OriginArgumentType and LayerArgumentType respectively)

• Trying to reference an invalid origin layer should now properly throw an exception.
  (Previously, it wasn't throwing an exception which can cause some interesting issues such as preventing the NBT of the player from being saved)

• The suggestions list of the origin argument type should now depend on the specified origin layer of the origin layer argument type (e.g: only origins registered in the origin layer will be displayed). If the origin layer does not exist, it'll display nothing.
  ([BUG] All origins are displayed in the list suggestions for the <origin> argument of the /origin command #583)

[MerchantPug]

Ignore the two above references, I was just stating how I was missing this implementation in my porting process.