Support for multiple protocol versions

[caelunshun]

Work needed:

• Packet ID mappings for each supported protocol
• Block state ID mappings for each supported protocol
• Packet write() function needs to take a protocol version so different versions can have varying packets
• Rewrite packet derive macro to support multiple versions

[aramperes]

Is the intended outcome to support multiple protocol versions in the same build (similar to ViaVersion/ProtocolSupport compatibility), or having different builds for each supported version?

I think the latter would be better since we'll also want to support multiple versions of world saves eventually, and it would be safer to support only one version per build.

[skillman623]

Would it be possible to use Stevenarella's protocol support?
https://github.com/iceiix/stevenarella/tree/master/protocol
If implemented it contains support for versions 1.7.10-1.16.1.