QCNN should support layouts other than MERA

[SaashaJoshi]

This paper proposes several layouts for a Convolutional Neural Network model that must be added to the repository.

T. Hur, L. Kim, and D. K. Park, “Quantum convolutional neural network for classical data classification,” Quantum Machine Intelligence, vol. 4, no. 1, Feb. 2022, doi: https://doi.org/10.1007/s42484-021-00061-x.

Currently, the QuantumConvolutionalLayer defaults to a MERA structure, which must be changed to an optional feature.