Add support for "view_mode_selector" field type

I think there's no need for a separate field processor plugin, it may be done via SimpleFieldDeriver.
Ref ✨ Support geofield field type Fixed for an example.

Tests are failing due to the View Mode Selector module bug: 🐛 Warning: Undefined array key "view_mode" while creating the field Active .
Once it's fixed and tests passes, we should be good to go.