[IOT-1808]Changes in C++ APIs to remove TopicList raw pointers.

[IOT-1808]Changes in C++ APIs to remove TopicList raw pointers.

1. Changes in NSProvider APIs for get and set TopicsList to shared pointers.
2. Changes in NSConsumer API for get ConsumerTopicList to shared pointer
3. Changes in NSProviderService API to get RegisteredTopicsList to shared pointer.
4. changes to return as object of list of Topics in TopicsList

Patch 2 : rebased

patch 3 : added shared_ptr changes to setTopicList as per review

patch 4 : added modifiability feature for preventing TopicsList modification
patch 5 : added unsetModifiability to only preven modification
patch 6 : rebased

Change-Id: I3aacef4f3a5809623add69a16fd2ad9f93d11dd9
Signed-off-by: abitha.s <abitha.s@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17113
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>