Subfield types list_string, list_integer

Problem/Motivation

As reported in 🐛 Improve field, filter, argument and sort types for views Fixed , currently subfield defined as select fields with label/value mappings are not fully used in views - the value is always shown instead of the label.

Steps to reproduce

Create a custom field with a list subfield (integer or string values) and define key/label mappings.
Create a view that displays that subfield: the value is shown and not the label.

Proposed resolution

Add support for list_string and list_integer.

Remaining tasks

N/A

User interface changes

TBD

API changes

N/A

Data model changes