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.

[dennisYatunin]

I think this looks mergeable, save for some minor nitpicks. If you want to check this with ClimaAtmos before merging, feel free to define some aliases like const AxisTensor = Tensor, which I used to ensure backward compatibility when refactoring RecursiveApply.

[dennisYatunin]

Suggested change

	@inline outer(x::AbstractVector, y::AbstractVector) = x * y'
	@inline outer(x::AbstractVector, y::Number) = x * y
	@inline outer(x::AbstractVector, y) = nested_broadcast(y -> x ⊗ y, y)
	@inline outer(x, y) = x * y'

Both * and ' already call nested_broadcast, and you can call ' on a Number (that's just a no-op).

[dennisYatunin]

This also looks like a relic from before the RecursiveApply refactor.

[dennisYatunin]

This case is already covered by the method below.

[dennisYatunin]

I feel like testing the padded FLOP counts here doesn't serve much of a purpose. You can leave it in if you want, but we only need tests like this for sparse tensors, which won't be introduced until a future PR.

[nefrathenrici]

I'll remove them, they don't make sense with the uniform padded storage.