Add QCQMC code part 1

[fdmalone]

Adds the top level modules from the qcqmc code repo:

1. data: a light module for creating the data/ folder structure which is assumed throughout the code.
2. utilities: various utility functions (I already know this is going to be rejected :))
3. afqmc_circuits. Cirq circuits implementing some circuit primitives for the AFQMC trial wavefunction.

Also adds the requirements.