Custom component in GridPro should support HasValueAndElement instead of AbstractField

[probert94]

Describe your motivation

I would like to use custom editor components in the GridPro and some of those components extend Composite or AbstractCompositeField. Unfortunately the GridPro only accepts AbstractField as custom editor component.

Describe the solution you'd like

After taking a look at the source, it seems like HasValueAndElement could be used instead of AbstractField.
HasValueAndElement supports all the needed methods (getElement, getValue, setValue) and as it is an interface, it could be used for every component.
As AbstractField already implements HasValueAndElement, the change should be compatible with the current version.

Describe alternatives you've considered

The only alternative seems to be to rewrite all the components to extend AbstractField. In the worst case this is not even possible, as the components might come from a third party library.

[juuso-vaadin]

A customer has requested this in order to be able to use LookupField add-on in GridPro.