[libcommhistory] Only resolve contacts for event models when explicitly requested

Only a minority of ConversationModel or CallModel instances actually use contact information. It's not always available to applications, and it's expensive to query. It shouldn't be enabled unless the application asks for it.

After this change, you must call setResolveContacts(true) for any EventModel subclass that should resolve and update contact information. There are actually very few of those cases in maintained software that aren't already broken (due to expecting contacts from SyncModel queries - that hasn't worked since Tracker). I will update those packages.

The declarative models are updated so they're able to take advantage of the resolved contacts properly.