ENH: Refactor `itk::ImageRegistrationMethodv4` statements into methods

[jhlegarreta]

• ENH: Refactor itk::ImageRegistrationMethodv4 domain clearing methods
• ENH: Group setting itk::ImageRegistrationMethodv4 random seeds
• ENH: Refactor itk::itkImageRegistrationMethodv4 dependent statements

PR Checklist

• [X] No API changes were made (or the changes have been approved)
• [X] No major design changes were made (or the changes have been approved)

[jhlegarreta]

/azp run ITK.macOS

[hjmjohnson]

@jhlegarreta This is nearly 2 years old. Is it relevant? If so, please resolve the conflicts.