[IOT-1824] Add an API to request a WiFi Connection to Enrollee

[IOT-1824] Add an API to request a WiFi Connection to Enrollee

This API would be helpful to Enrollee when it destroys its Soft AP network
and tries to connect an WiFi AP with given WiFi information from Mediator

oic.r.easysetup resource
 + "connect" or "cn" property
    - type: array of integer(enum)
    - e.g., "cn" : [ 1 ] or ''cn" : [ 2 ] or "cn" : [ 1, 2 ]  // 1 : WiFi, 2 : BLE , 3 : other transport to be added in a future

Change-Id: I476c95696c8df243e83232cedc27852c875b2dbe
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17061
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Heewon Park <h_w.park@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>