Surveyor Map Framework

Changes:

• Re-encode player terrain exploration using region bitsets and positions encoded as longs.
• Implement structure exploration using a similar format to chunk structure references
  • Exploration checking is run every 8 ticks, and only includes structures referenced in the current chunk or the chunk of a player block raycast.
  • To be explored, the player or their looked-at block have to be both within the overall structure bounding box, and within one of the structure piece bounding boxes.
• Refactor the world structure summary to use a cleaner set of maps for storage
• Add structure tag saving and syncing to let client mods use structure tags.
  • note that these are effectively just wrapped IDs - for ID matching - we haven't revived the structure registry in any way.
• Change the packet format to match the above.
• Send missing landmarks on join
• Change a few packet IDs

Changelog: https://github.com/sisby-folk/surveyor/releases/tag/v0.1.0-alpha.10