to handle creation of parameter definition widgets
Previously, these configuration widgets were all hardcoded into the Python modeler
dialog. This prevented 3rd party, plugin provided, parameters from ever being full
first class citizens in QGIS, as there was no way to allow their use as inputs to
user created models to be customised.
Now, the registry is responsible for creating the configuration widget, allowing
for 3rd party parameter types to provide their own customised configuration
widgets.
Refs #26493
