Add package: dynamicprops.yaml

[farhi]

Add contribution 'dynamicprops':

• Matlab-compatible superclass allowing to add new properties dynamically.

Dear Octave package maintainers,
here is a contribution for a dynamicprops class which works similarly as in Matlab.

• https://fr.mathworks.com/help/matlab/ref/dynamicprops-class.html

I have formatted the documentation in the style of Octave texinfo, and added a test at the end of the dynamicprops.m file.

Thanks for your work !
Emmanuel.

[siko1056]

Thank you for the package contribution @farhi 👍