Our CI plans fail from time to time in the test which is based on the OS-selected port * Change the port to use a `SocketUtils.findAvailableTcpPort()` since all other with the fixed port don't fail * Rework all the RMI tests to JUnit 5
Our CI plans fail from time to time in the test which is based on the OS-selected port * Change the port to use a `SocketUtils.findAvailableTcpPort()` since all other with the fixed port don't fail * Rework all the RMI tests to JUnit 5