Add position and rotation components to Camera entities

[cart]

Currently camera position and rotation must be handled by directly modifying the Transform component.

This should be reconciled with manually setting the Transform (ex: calling look_at()). We don't want position and rotation components overriding manually set transforms.

[cart]

Fixed by 21a79c5, which adds the ability to toggle syncing from pos/rot components to transforms. But this isn't an ideal solution. I would prefer it if changes to LocalToWorld transforms automatically synced to Translation, Rotation, Scale components and vice-versa, but I'm pretty sure we need component change events for that to work properly.