Find better way to figure out own name/number

[hyfen]

Currently, ImessageTransformer needs config passed in to build your own name/number. Ideally, we need a more automated way of determining this information.

For iCloud, we can use what we did with Safari to detect currently logged in iCloud account: https://github.com/chronicle-app/chronicle-safari/blob/0252fab1d882bd3b491059ccec61610721b33653/lib/chronicle/safari/safari_extractor.rb#L44.

For SMS, we still need would need an automated way to determine your own phone number. It should be possible to find in chat.db but needs more sleuthing.

The name/phone settings should still exist as an override in case you're extracting from a chat db that's not associated with your logged in iCloud account.