STYLE: Improve ivar printing in `PrintSelf` methods

[jhlegarreta]

Improve ivar printing in PrintSelf methods:

• Use the itkPrintSelfObjectMacro macro to avoid boilerplate code when printing smart pointers/objects that can be null pointers.
• Rely on the enum classes ostream insertion operator overload to directly print such variables. Avoid boilerplate code.
• Increase consistency when printing boolean ivars: use the ({ivar} ? "On" : "Off") recipe in agreement with the ITK SW Guide.
• Do not check whether std::string types ivars are empty to conditionally print their contents; rely on the ostream insertion operator overload to print the appropriate content.
• Print the member variable names verbatim to conform to the ITK SW Guide.
• Prefer using std::endl instead of \n to add a new line for the sake of consistency.

Take advantage of the commit to print ivars that had been missed in the modified classes.

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]

Realized about these when resuming work on #3908. By no means this PR is intended to be extensive in the changes: separate, incremental PRs as code is inspected can be done.

[jhlegarreta]

/azp ITK.macOS

[jhlegarreta]

ITKmacOS failures are unrelated:

ld: warning: ignoring duplicate libraries: '-lm'

https://dev.azure.com/itkrobotmacos/ITK.macOS/_build/results?buildId=11648&view=logs&j=a5e52b91-c83f-5429-4a68-c246fc63a4f7&t=5add3200-7efa-59c0-0a45-43bce0c77c69&l=8555

Tests are passing: https://dev.azure.com/itkrobotmacos/ITK.macOS/_build/results?buildId=11648&view=ms.vss-test-web.build-test-results-tab

https://open.cdash.org/viewBuildError.php?type=1&buildid=9723501

Same applies to ITK.macOS.Python: https://dev.azure.com/itkrobotmacospython/ITK.macOS.Python/_build/results?buildId=10403&view=ms.vss-test-web.build-test-results-tab

https://dev.azure.com/itkrobotmacospython/ITK.macOS.Python/_build/results?buildId=10403&view=logs&j=a5e52b91-c83f-5429-4a68-c246fc63a4f7&t=5add3200-7efa-59c0-0a45-43bce0c77c69&l=3542