This is replaced with a QVariantMap. It was never really more than this in the
past and with the switch to QgsConfigurationProperties, there is really no
longer any reason to assume that this will change.
Now the widgets factories can give a score on how good they could handle
a widget.
Additionaly, plugins can be added to choose a widget factory in function
of an external information. One of them uses a table in PostgresQL to
allow specification of the widget type and configuration.
I took the opportunity to remove a few deprecated method in relation to
this.
