[Easy-Setup] Arduino Enrollee Doxygen update and api folder change

[Easy-Setup] Arduino Enrollee Doxygen update and api folder change

- Reused OCConnectivityType struct instead of defining new struct
- Updated the Enrollee Device doxygen comments
- Enrollee EasySetup API folder is changed
- License header contribution year is updated

Change-Id: I72e095c5c886fb10dd365b72c80944f8864685ee
Signed-off-by: Madan Lanka <lanka.madan@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/3413
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
(cherry picked from commit 67ecf55a724ba906e12e9986bb8e04f77a4f6a06)
Reviewed-on: https://gerrit.iotivity.org/gerrit/3455