Performance issues on huge data tables

Summary

When visiting the feedback history or the participants' overview with many entries in the table, the performance is very poor. We should come up with an idea to fix these performance issues.

Steps to reproduce

Import data with lots of participants, then go to the participants' overview when logged in as reviewer.

Possible fixes

• Use pagination on the corresponding data tables
• Find out what affects performance the most, then try to reduce performance impacts (possibly reactivity problems)