Default copy and move of iterators, using ITK_DEFAULT_COPY_AND_MOVE

[N-Dekker]

Replaced hand-written copy-constructors and assignment operators of four iterators with the equivalent ITK_DEFAULT_COPY_AND_MOVE macro calls.

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• Follow-up to pull request Add ITK_DEFAULT_COPY_AND_MOVE and replace "manually" defaulted copy and move member function declarations #4652

[dzenanz]

Looks great on a glance!

[N-Dekker]

I did look carefully at those hand-written copy-constructors and assignment operators to check that they really just do "the default thing". But honestly an extra glance wouldn't harm 😃

Note that some copy functions of other iterators seem to do non-default things, for example:

• the copy-constructor of ConstNeighborhoodIterator:

  ITK/Modules/Core/Common/include/itkConstNeighborhoodIterator.hxx

  Line 240 in efe3dce

  this->ResetBoundaryCondition();

• the copy-constructor of ImageConstIteratorWithIndex:

  ITK/Modules/Core/Common/include/itkImageConstIteratorWithIndex.hxx

  Line 46 in efe3dce

  m_PixelAccessorFunctor.SetBegin(m_Image->GetBufferPointer());

I did not include those seemingly non-default-behaving copy-functions with this pull request.