Fix a limitation of the maximum number of child resources of a collection

Fix a limitation of the maximum number of child resources of a collection

We found that there is the maximum number of child resource able to be
registered to a collection resource which is 5. This commit is to eliminate
the limitation by using link-list rather than static array allocation
(refer to ocresource.h in csdk folder).

Change-Id: I23e9d200ae39b33497d8fd9863adb9dbadfb3c70
Signed-off-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5037
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: John Light <john.j.light@intel.com>
Reviewed-by: Junghyun Oh <junghyun.oh@samsung.com>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>