No log messages comming from Elytron - kerberos

Elytron is missing log messages related to kerberos authentication. These log messages should be added. See JBEAP-6041 for more details.

I consider to be useful to have TRACE log messages at least in:

• SpnegoAuthenticationMechanism
• GSSCredentialSecurityFactory

If there are more classes involved in kerberos authnetication include them as well.

Kerberos issues are very specific. So it is very important to have as much trace information as possible. Therefore raising priority to Critical.