Display information from a linked entity in a table

[sleidig]

As a user I want to see details like the gender of participants in the participants table of a school/team details view.

At the moment, we can only display an "entity block" (including the name/toString of the linked entity) in the table but not access any fields of that referenced entity.

We should probably cache the linked entity rather than loading it every time in every table cell for this to avoid performance problems.