* migrates lib/foundation and lib/widgets

* migrates lib/painting and lib/material

* migrates lib/cupertino, lib/gestures, lib/services, lib/semantics and lib/rendering

* fixes failing tests

* migrates test/

* improves hashing of lists

Update samples to use repo analysis options, Fix sample templates and a ton of analyzer issues (#77868)

* migrate material to nullsafety

* address review comments

* address review comments

* fix build

Create a new TextSelectionTheme for text selection properties.