Some nested classes should be considered to be static nested in Elytron

There are some inner classes in Elytron which should be considered to be static nested to avoid dependency on their outer class. Following nested classes should be considered:

• LoadedIdentity and Identity from org.wildfly.security.auth.realm.FileSystemSecurityRealm
• DecoderState from org.wildfly.security.asn1.DERDecoder
• AccountEntry from org.wildfly.security.auth.realm.LegacyPropertiesSecurityRealm
• JaasAuthorizationIdentity and DefaultCallbackHandler from org.wildfly.security.auth.realm.JaasSecurityRealm
• LoadKey from org.wildfly.security.keystore.AtomicLoadKeyStore