Cheap Static/Config data tables

Right now it is reasonably expensive to load in physics, terrain, or nav data during a "tick" which is the hottest path. Ideally we have some first-class support for a cheap read-only table that can be initialized at startup. Right now there is the potential to use a const or static but with caveats so having the team support this pattern out of the box would be really valuable.

For example, I have navmesh grid data that is ~8mb. I need to load in ~200 bytes * 9 (for the chunks surround) per moving entity. So if I have 100 players and maybe 1000 monsters running around thats 1,1002009 potentially bytes read every ~100ms when I never need to edit this data.

I can simply add this data into a const and bundle it with the module but it doesn't feel like "the spacetimedb way" of doing things. If something is 100% read only I'd like a way to read that data for close to free instead of the charge at the same rate as hot data.

Requested by @onx2 via the SpacetimeDB site.

The issue names no files, tests, or entry points. Start by mapping how physics, terrain, or nav data is loaded and charged during a tick, then compare the const/static workaround with startup initialization; done should be a defined first-class read-only table path with near-free reads.