Support get/set subscription property

1. Support getSubscriptionProperty.
2. Added group update support. Setting some fields in the
   subscription will automatically apply to the other
   subscriptions in the group.

Bug: 239607619
Test: atest SubscriptionManagerServiceTest
      atest SubscriptionDatabaseManagerTest
Merged-In: I7f11230398183a54a766d0b6c19a0e36dae70d6d
Change-Id: I7f11230398183a54a766d0b6c19a0e36dae70d6d