Add smart date field inside the Date and Time category

Problem/Motivation

With the new field_ui overview, there are icons for the core fields. As the module provides a field type, it should also provide an icon or a better solution like under the date and time category.

Steps to reproduce

Add a field to an entity.
See the missing icon.

Proposed resolution

Look into how we can add the smart date field inside date and time category

Remaining tasks

Create MR
Update documentation/readme
Review MR
Approve MR

User interface changes

Remove field from field_ui overview and add this inside the smart date category.