Add two APIs in EnrolleeConf class

Add two APIs in EnrolleeConf class

The two APIs are added in EnrolleConf class so that provisioning status
and last error code properties can be passed to application as a response
of getConfiguration API call.
Note that those APIs are already provided in EnrolleeStatus class which
is a GET request with baseline interface.

Change-Id: I46133a189fff5201df9526bf2ef6009834ab77ab
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18445
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Heewon Park <h_w.park@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>