Add sketch of new Tensor interface

[dennisYatunin]

This PR refactors the Geometry module to use a much simpler interface, so that all vector/tensor operations can expressed using standard math operations instead of custom API functions. This will allow us to remove a large amount of duplicate code, reduce compilation latency, and speed up GPU runs by optimizing the geometry data passed to each kernel.

• Code follows the style guidelines OR N/A.
• Unit tests are included OR N/A.
• Code is exercised in an integration test OR N/A.
• Documentation has been added/updated OR N/A.