engine: Add AuditLogDirectorDelegator as a non-static version of AuditLogDirector

AuditLogDirectorDelegator provide the non-static log methods which can
be mocked in unit tests.

Change-Id: I82f6b81c10da58bdf6e84934a6388e43f095179f
Signed-off-by: Yevgeny Zaspitsky <yzaspits@redhat.com>