Add base "BVH" class, LineSegmentsBVH, PointsBVH

[gkjohnson]

Fix #243

• Adds support for a PointsBVH, LineSegmentsBVH, LineBVH, LineLoopBVH
• Adds an abstract base class for construction of the above

TODO

• Cleanup
• Performance tests
  • Construction
  • Raycasting

Future

• Refactor: Ensure consistency between BVH implementations, naming #819
  • Rename "MeshBVHHelper" to "BVHHelper"
  • Handle other functions (like "validate bounds")
  • Deprecate "maxLeafTris"
  • Update serialize across other bvh types
  • See if "refit" can be moved
  • Get workers functioning
• MeshBVH: Indirect option overhaul #818
  • Possibly switch "indirectBuffer" to align with "indexArray"
• Create abstraction to support a Scene BVH #388
  • Add a "StaticSceneBVH" that supports arbitrary objects, BatchedMesh, InstancedMesh for queries
• Test / Improve tree-shakeability #820
  • Fix "built in" raycasting logic since we need original raycasting functions
• BVH: Adjust BVH to not depend on geometry, indirect buffer #821
  • Remove need for "indirect" buffer access in build step
  • Remove need for "geometry" from "build" step
• MeshBVH: Indirect option overhaul #818
  • Clean up template functions, simplify need for "indirect" cast functions