Description

Move the projectq and sympy simulator to their own repositories and their own pip packages.

Checklist

• create the sympy repository https://github.com/QISKit/qiskit-addon-sympy
• move the sympy simulator code to the repository
• remove the sympy simulator from qiskit-core Remove Sympy simulators for moving to new repository #514
• create the sympy pip package and the documentation (README.md, etc)
• create the projectq repository https://github.com/QISKit/qiskit-addon-projectq
• move the projectq simulator code to the repository
• remove the projectq simulator from qiskit-core Remove ProjectQ from qiskit-core #553
• create the projectq pip package and the documentation (README.md, etc)

See also

#413: previous issue with 0.5 planning
https://github.com/QISKit/qiskit-addon-sympy

(original description by yaelbh)

Directory qiskit/backends/local currently contains (in PR #421) backends qasm_simulator_projectq.py and statevector_simulator_sympy.py
It cannot contain qasm_simulator_sympy.py, because the Sympy simulator is state vector only.

Task: write statevector_simulator_projectq.py

In addition, there is a request to move ProjectQ and Sympy backends to qiskit-core-backend-plugins. @ajavadia, do you have a more concrete specification for that?