Add EasySetup class and Update RemoteEnrollee class for Android Mediator

Add EasySetup class and Update RemoteEnrollee class for Android Mediator

1. The previous EasySetupService class is inconsistency to the class for C++
SDK.
  - Rather, EasySetup class looks better.

2. createRemoteEnrollee API is get to have void parameter

Note that, we will add several APIs in these classes when they are implemented.
And useless files will be removed soon.

Change-Id: Iacb665bb16d1c9e8be2525801dd8a0d4613234d0
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/8705
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>