Adds //iteminfo command

[elftausend]

Adds iteminfo command as described in #30

[platz1de]

Information about defence or max durability don't really fit the scope of a world-editor, there are other plugins to do that
I don't see much point in an iteminfo command other than debugging (printing formatted nbt for bedrock & java equivalent)

[elftausend]

Makes sense. I could remove the unrelated info and implement printing the nbt data, if that's okay.
Anyways, could you please either close #30 or update the labels, scope, etc?

[platz1de]

The issue is still relevant and will be implemented with the exception of max durability, so no reason to change anything about it

About this pr then:
To be consistent with block info, the default message format should be for example:
{count}x {name} ({id}:{meta})\nItem data: {nbt}\nJava data: {java_nbt}
for the id, the stringy id is more useful (runtime ids are only displayed for legacy purposes) and can be directly gathered from the item serializers (or just extract it from the nbt)

Here's an example of how the data command of java edition renders nbt