Update imports to use JUnit 5 instead of JUnit 4 (#11425)

* Update imports to use JUnit 5 instead of JUnit 4
* Add commonly used JUnit 4 classes to forbidden packages

Related to: https://github.com/openhab/openhab-core/pull/2534

Signed-off-by: Wouter Born <github@maindrain.net>

bundles/org.openhab.binding.fmiweather/src/test/java/org/openhab/binding/fmiweather/AbstractWeatherHandlerTest.java

@@ -12,7 +12,6 @@
  */
 package org.openhab.binding.fmiweather;
 
-import static org.junit.Assert.assertNotNull;
 import static org.junit.jupiter.api.Assertions.*;
 
 import java.lang.reflect.InvocationTargetException;