New pin field type: Dropdown (single and multi-select)

As a user, I would like to be able to use a new user-defined pin field of the "Dropdown" type, in which I can select predefined values either as a single selection (Single Select) or multiple selection (Multi Select) in the pin.

The selection should be made via a drop-down menu so that structured entries are possible - for example for states, categories or responsibilities.

In addition, I would like to be able to filter according to these selection values later on in order to be able to evaluate or process pins efficiently.