[RN] Implement suggestions for JGroups integration w/ Elytron

Incorporate pferraro@redhat.com's feedback into the release notes:

In the section entitled "Elytron Integration With the JBoss EAP Subsystems", the jgroups section mentions ASYM_ENCRYPT and SYM_ENCRYPT, but does not mention AUTH, which can also configure its shared secret from an elytron-managed credential store, and in the case of a cipher-token, can obtain the keys used to encrypt the shared secret via an elytron-managed key store.