Unify cellular sheaf interface

All types of cellular sheaves should implement the same interface.

I'm envisioning three main types of cellular sheaves:
1. Single threaded
2. Multi-threaded
3. Distributed (MPI)

Each of these types also probably need variants with edge potential functions.

The core functions that each of these types need to implement include
- Project a point to the nearest global section of the sheaf
- Apply the sheaf laplacian
- Apply the coboundary map

We should also implement conversions between the different types and adapt the cellular sheaf macro to be able to emit the different types.