Apply namespace OIC::Service.

Apply namespace OIC::Service.

moved Broker's whole class into namespace OIC::Service.
added exception of Broker API.
changed hostResource return type to const type.
changed cancelHostResource return type to void.
aligned source and header files.
Added initializer for each class.

Change-Id: I65278e2eab1c3621240e9242bdd3f07d592f7911
Signed-off-by: jyong2.kim <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1472
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>