CP tensor network support

Right now it is not possible to decompose a network which contains hyper edges. Therefore one cannot extract a sub-graph from a tensor network, decompose it, partially contract it with another sub-graph from the network, then decompose the mixed networks. This is a similar idea to decomposing one or multiple CPDs into a CPD with a different topology.

The issue names no files, tests, or entry points. Begin by understanding how hyper edges and CPDs are represented in ITensorCPD.jl, then define the decomposition workflow for extracted and partially contracted sub-graphs. Done should include support for decomposing networks with hyper edges and the mixed-network use case described.

Written by the indexing model from the issue text.