iOS system integration

[Giuliopime]

Integrate with iOS as deeply as possible:

• create list from image using app intent that receives image (also support from share sheet when image is shared)
• fix URLRepresentableEntity and URLRepresentableIntent not launching app with correct URL?
• Implement Transferrable protocol, with pdf, text and image types (maybe more types)
• Add SiriTipView (https://superwall.com/blog/an-app-intents-field-guide-for-ios-developers/) not pretty, prefer using TipKit
• Add OpenIntent for list item task (means implementing universal link navigation for those entities)
• Provide SnippetIntent to quick add task and item control widget, when supported https://developer.apple.com/forums/thread/760793?answerId=875649022#875649022
• Support upcoming and priority filters for today tasks widget