A collection of things that need to change when using Java 16

When LibX is packed as a module, it should not export the impl and annotation.processor packages. NetworkImpl has to get a wrapper then as it is used.

Done

ModInit should support the generation of codecs for records

Done

ImmutableList.of and methods like this should be replaced with List.of

Done

With the changes that are planned to the config system, it should be possible to automatically provide value mappers for record if there are value mappers for all element types.

Done

Use new instanceof syntax whenever possible

Done