Adding Qiskit import example to the qcor demo

- Execution: state-vector (`qpp`); noisy (`aer`); IBM; IonQ. Show QObj (IBMQ portal) to demonstate native gate set mapping (e.g. H -> rz and sx decomposition)

- Advance: increase number of qubits (~50) => MPS simulation (TNQVM); choose IBM pulse-mode (submitting pulses to IBM)

- Choose IBM pulse-mode (submitting pulses to IBM)

- Python binding: equivalent kernel expressed in Python (qjit)

- Python binding: `ghz.py` - QCOR IR from Qiskit

- IonQ: Create `.ionq_config` with 

/// QCOR IR compile and execution on backends:

/// "Write once run all"

/// Simulator

/// $qcor -qpu qpp ghz.cpp 

/// QPU (11 qubits)

/// qcor -qpu ionq:qpu ghz.cpp

/// Entangled state preparation:

__qpu__ void ghz(qreg q) {

  H(q[0]);

# Demonstate the ability to interop with other quantum programming framework/IR

# "Run all that is written"

from qcor import qjit, qalloc

# Import from Qiskit qiskit_circuit

import qiskit

# Generate 3-qubit GHZ state with Qiskit

qiskit_circ = qiskit.QuantumCircuit(3)

qiskit_circ.h(0)

qiskit_circ.cx(0, 1)

qiskit_circ.cx(1, 2)

qiskit_circ.measure_all()

# Convert Qiskit circuit to QCOR IR

qcor_kernel = qjit(qiskit_circ)

# Allocate the qreg

q = qalloc(3)

# Examine the QCOR IR:

print('QCOR IR:')

qcor_kernel.print_kernel(q)