sdk: implement support for user defined session authentication

This patch implements support for the user defined session authentication
instead of ordinal credentials,

what will let SDK consumers to reuse theirs JSESSION emulating SSO
authentication mecanism.

Change-Id: I8961f0aca7cc36210da8613399be44701dd087fb
Signed-off-by: Michael Pasternak <mpastern@redhat.com>