Usage of the [compareWith] attribute

[Karamuto]

I'm submitting a

[ ] Bug / Regression
[x] Feature Request / Proposal
[ ] Question

I'm using

NG Dynamic Forms Version: `6.0.7`

[X] Basic UI
[ ] Bootstrap UI  
[ ] Foundation UI
[ ] Ionic UI
[ ] Kendo UI
[ ] Material  
[ ] NG Bootstrap
[ ] Prime NG

Description

Like here it would be usefull, to be able to use the compareWith attribute on selectControls.

This could be realised the same way as custom validator functions and it would be possible to load async field data on open a select.