Backend module integration with WMI simulators and quantum computers

[TFphoenix]

This pull request aims to implement a backend module within qib, that can interchange experimentation requests and results over the network with various quantum providers and processors. This pull request also expands the backend module for the WMI provider (i.e. for their Qiskit Simulator and Quantum Computer backends). Other auxiliary changes, adaptations, and expansions of the existing codebase were proposed in this pull request.

Changes proposed in this pull request:

• A generic and fully-extendable infrastructure for the integration of quantum processors/backends with qib (i.e. the backend module), consisting of the following core components: QuantumProcessor, Experiment, ExperimentResults, Options (see this for a more detailed module architecture overview)
• An extension of the backend module for the WMI (Walter-Meissner Institute) provider (i.e. for their Qiskit Simulator and Quantum Computer backends)
• Additional quantum gates: Identity, iSwap, and SX
• An extension of the AbstractOperator: ControlInstruction which includes the measure, barrier, and delay quantum instructions
• OpenQASM 2.0+ serialization for quantum circuits, experiments, gates, and instructions
• A simple HTTP request-response network communication system
• UTs for all above-mentioned implementations
• Codebase syntax upgrade to Python 3.10
• A small refactoring and adaptation of the TensorNetworkProcessor
• Additional examples, consisting of a basic and a more advanced scenario, of utilizing the WMI provider using qib's backend module (WMI Backend Integration and Single-Qubit Quantum State Tomography Experiment, for both the WMI Qiskit Simulator and WMI Quantum Computer backends)
• Documentation on how to extend the backend module for future quantum backend providers (see here)