Handle default task list

[opatry]

• Expose isDefault in DB & business data models (Default task list API #195)
• Update UI data model to properly implement canDelete (Default task list API #195)
• Handle local only setup for default task list (local ID == 1) (Default task list API #195)
• Provide TaskListsApi to resolve the @default task list. (Default task list API #195)
• Sync with remote side to determine which list is the default one
  • Relates to Fully implement and test sync #140
• Reflect it in DB table (requires a migration)
• Ensure there is only one default list in table, in case of conflict, the remote default one wins