Use parameterized circuits to speed up some algorithms instead of using CircuitCache

[chunfuchen]

Summary

Use parameterized circuits to speed up some algorithms instead of using CircuitCache; however, in this case, the parameterized is not an algorithm-agnostic module to support different algorithms, the algorithm needs to handle the stored circuits by its own. Thus, this PR uses parameterized circuits for some algorithms as a starting point, if an algorithm keeps using the circuits with the same topology many times, the algorithm could be re-written in a similar to improve the speed.

Details and comments

1. Re-write VQE, VQC and QSVM via parameterized circuits as a robust alternative to CircuitCache
2. Add a flag in FeatureMap and VariationalForm to indicate whether or not it can take Parameter. and then use it to construct a template circuit.
3. QuantumInstance add transpile method to accommodate the algorithm needs to store the transpiled and parameterized circuits.
4. Remove circuit cache.
5. The travis CI won't pass until this issue is fixed Support unary operand for ParamterExpression Qiskit/qiskit#3098.
6. I think QGAN could be sped up by parameterized circuits.