Figure out what to do about use of qiskit.utils validation.py

[woodsp-ibm]

That file was used by algorithms to validate parameters and have consistent error messages. Though in Qiskit its only used by algorithms (came from Aqua originally) and so I imagine it likely to be removed from Qiskit.

Related to #21

See also Qiskit/qiskit#10516 where its noted and I suggest that simply making a copy here and switching the algorithms to use that here is likely all that is needed on this side since validation is all internal logic here.