Add dynamically updating tiled navmesh example

[isaac-mason]

Support this kind of functionality: https://www.youtube.com/watch?v=WzFJMvE0L60

[isaac-mason]

WIP: https://sketches.isaacmason.com/sketch/recast-navigation/dynamic-tiled-navmesh

This example generates navmesh tiles in a pool of web workers, updating navmesh tiles that have active physics bodies in them (using rapier.js).

Should look to create a minimal demo here.

There's a DynamicTiledNavMesh class in that example that could be improved and included in a non-core package, e.g. recast-navigation/addons: https://github.com/isaac-mason/sketches/blob/main/src/sketches/recast-navigation/dynamic-tiled-navmesh/navigation/dynamic-tiled-navmesh.ts

[GGAlanSmithee]

this is really cool @isaac-mason 💯