Rudder

It seems that the visibility of some util classes changed in open jdk17, and when we try to compile rudder with it, we get an error:

[2021-11-22T17:00:43.647Z] java.util.concurrent.ExecutionException: Boxed Exception

[2021-11-22T17:00:43.647Z] Caused by: java.lang.IllegalAccessError: class com.normation.rudder.services.servers.AllowedNetwork$ (in unnamed module @0x6c50245e) cannot access class sun.net.util.IPAddressUtil (in module java.base) because module java.base does not export sun.net.util to unnamed module @0x6c50245e

[2021-11-22T17:00:43.647Z]     at com.normation.rudder.services.servers.AllowedNetwork$.isValid(PolicyServerData.scala:88)

I'm setting target = 6.2, but depending on the reach of the change, we may need to correct it only in 7.0. This does not seem like a showstopper since java 11 works well with rudder and is an LTS that should outlive rudder 6.2 support.