pjsip_options: Schedule/unschedule qualifies on AoR creation/destruction

pjsip_options: Schedule/unschedule qualifies on AoR creation/destruction

When an AoR is created or destroyed dynamically, the scheduled OPTIONS
requests that qualify the contacts on the AoR are not necessarily started
or destroyed, particularly for persistent contacts created for that AoR.
This patch adds create/update/delete sorcery observers for an AoR, which
schedule/unschedule the qualifies as expected.

Change-Id: Ic287ed2e2952a7808ee068776fe966f9554bdf7d