Move `numpy=1.16.4` from all over the place into component/numpy.
Don't move if a different numpy version is used, or it looks like a
software cares to use exactly particular version.
Downgrade pygolang/test.cfg from numpy=1.16.6 to numpy=1.16.4 and use
common numpy component version - using numpy=1.16.6 is not required for
pygolang testing and so this downgrade is acceptable. It will be better
to upgrade NumPy to latest in component/numpy/ as a future separate step.
See previous patch where it was decided and explained that version for
component <X> lives in component/X/.