Move data configuration into the database

[googol]

This includes the fields available in the participant list and details view, and which of them are searchable in the list view. The mapping from kuksa to these fields should also be defined in the database.

The goal is to make setting up reki easier. Configuration of the system for use should not require programming skills. With this change the configuration could be set with any postgres client, still requiring some technical skill, but enables further development