[FEATURE] Let the relator display "as a label" (bolded etc).

[rosiel]

Overview of feature request

When viewing a Linked Agent field, the field value includes the relator, a colon, and the value. However, this can be hard to scan. Ideally the relator could show up "like a label" for the content it describes.

It's this line here: https://github.com/Islandora/controlled_access_terms/blob/2.x/src/Plugin/Field/FieldFormatter/TypedRelationFormatter.php#L32

What kind of user is the feature intended for?
Site Designers

What inspired the request?
Trying to put metadata display into a table, and realized Linked Agents looked a little funky.

What existing behavior do you want changed?
Concatenating the relator to the value

Any brand new behavior do you want to add to Islandora?
Use something else - template? - to let the relator and value be formatted (incuding as a label to match other field labels?)

Any related open or closed issues to this feature request?