Adds value conversion tables to perform lazy computations of lookup tables for mapping from a uint16 value to a float in [`lower_bound`, `upper_bound`].
Owners of the value conversion tables are `SubmapController`, `PoseGraph2D`, `ActiveSubmaps` and `ProbabilityGridPointsProcessor`. For concurrency reasons, having only a single owner is not possible.
Follow up PR in `cartographer_ros` is prepared.
- Adds TSDF2D Grid
- Adds tests for TSDF2D Grid
- Introduces Grid2D::GrowLimits(...) for multiple grids to reduce code duplication between TSDF2D and Grid2D