Customize pinned Fields on Entity View

Description

We make the current units (single-select, to-many relation to User) work for a dynamic schema:

customize pinned Fields: show/hide, change order [prototype]
only those who can edit pinned Fields see the ... control
so far, only single-select and to-many people Fields are available in the configuration
🦄 in-place drag'n'drop to change order is nice to have

Things to do on the UI

Make Reference Selector in popup great again: add the field name and some spacing to popup. Reuse context value selector control somehow.

Apply the same reference filter reference has in the object editor

Display empty value, allowing open the popup and choose the value.

Show only avatar without a label in the avatar unit

Make the Unit reusable, try to place it on other views.