Add `Split2qUnitaries` to the C API

[mtreinish]

What should we add?

Right now the Split2qUnitaries is written primarily in Rust but still has some dependency on Python. We need to have an implementation that doesn't rely on Python when being called from the C API and then add a standalone function to the C API as described in #14245

[raynelfss]

I'd say this one is ready to be picked up, the only strange thing happens when using DAGCircuit::replace_node_with_1q_ops where a very strangely placed py token seems to be required by the function.