[godot4] Use Godot TileMap for Rendering

[pcen]

There is a larger performance overhead for rendering the tilemap compared to how the map is currently rendered, but the frame rate does not decrease nearly as much when more of the map becomes visible

The following features are added in pull requests based on this branch:

https://github.com/C7-Game/Prototype/pull/408 adds units to this branch - merged https://github.com/C7-Game/Prototype/pull/412 adds cities - merged https://github.com/C7-Game/Prototype/pull/419 adds grid view - merged https://github.com/C7-Game/Prototype/pull/421 adds fog of war - merged https://github.com/C7-Game/Prototype/pull/422 adds horizontal wrapping - merged