STYLE: Merge common code using ctkMessageBox

[JEHoctor]

I saw an opportunity to increase code-reuse surrounding the ctk.ctkMessageBox dialog. In addition, several functions can become static methods.

[JEHoctor]

Let's not merge this right away as we need to give Lucia et al. time to evaluate PRs #45 and #47.

[jcfr]

Thanks for working on this.

I suggest to remove the display of Q3DCLogic.warningMessage(' Node not modified') and instead use slicer.util.confirmYesNoDisplay

The fact the node has not been modified is not relevant to the user and require the user to click on OK

[JEHoctor]

I was thinking of using slicer.util.delayDisplay for that. Note that as currently written, that message is displayed with the default is_query=False parameter, and so only an "OK" button will be on that dialog. It looks like slicer.util.confirmYesNoDisplay has both a "yes and a "no".

[bpaniagua]

Hi @JEHoctor

Can you please work on a commit to address the suggestion done by JC?
Thank you!

Bea

[bpaniagua]

Resurrecting this issue. Should we close this MR or complete it and merge it @jcfr