MB-10415 moxi and sample loader should use auth token instead

...of user/pwd combination since the password won't be stored
in config after MB-10415

Change-Id: I0780ee45a885187cbdf31b65a329928dbc0f262a
Reviewed-on: http://review.couchbase.org/34617
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>