Gson-style streaming NBT reader/writer API

[zml2008]

I'd like to introduce a streaming API for working with adventure-nbt, in order to become more flexible with data wrangling, and allow operations on the NBT stream without having to build a whole tree data structure.

This would likely involve:

• designing the streaming reader/writer interfaces
• replacing the existing BinaryTagIO.Reader/Writer system
• integrating with the SNBT reader/writer system
• handling things like depth or length limit as wrapper readers & writers (do we want Forwarding* interfaces)