Change a coap cloud server address to sign-up and sign-in

Change a coap cloud server address to sign-up and sign-in

An address of coap cloud server for testing is changed to 13.124.29.169.
And an access token issued by github has no expiry time so refreshtoken
is not used anymore.

Change-Id: Ib8ef89bc075114374dd345b79f7205ec99918c7d
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18687
Reviewed-by: Heewon Park <h_w.park@samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>