Move replace_link_variables_by_paths function in plone.app.contenttypes.utils to plone.base. Use it in plone.app.z3cform instead of its local clone.

[yurj]

the function replace_link_variables_by_paths is defined in:
https://github.com/plone/plone.app.contenttypes/blob/master/plone/app/contenttypes/utils.py#L29

There's the same exact function with the same code, defined here:

https://github.com/plone/plone.app.z3cform/blob/master/plone/app/z3cform/utils.py#L68

This plone.app.z3cform is used in the converter:

https://github.com/plone/plone.app.z3cform/blob/3bf3c73d7139cd1a2fddeb7aa694e3b7b1734b9e/plone/app/z3cform/converters.py#L524

while https://github.com/plone/plone.restapi/blob/main/src/plone/restapi/serializer/dxfields.py

uses the one from plone.app.contenttypes.utils

A solution could be to move plone.app.contenttypes.utils.replace_link_variables_by_paths to plone.base and remove the one in plone.app.z3cform.

cc: @jensens