1.16.1 support

[Gjum]

• switch to and update https://github.com/Gjum/jmcdata

need block data, see PrismarineJS/minecraft-data#236

use new ids and re-add block properties (reverse of these commits: af49a09, 913d45e)

McProto only supports one MC version at a time; if we want multi-version support, consider wrapping primitives (Hand, GameProfile, ...) and shading multiple McProto versions under different package paths in one big jar.