This reverts commit 2c2c8a75.

* Create state restoration templates, 

* Update existing state restoration samples to use the new templates

* Add to README, decided to require stateful widgets to include RestorationMixin

This reverts commit 8c44abc0.

Adds the rest of the scaffolding for building a UWP application. The actual build functionality needs to be implemented, but could use buildWindows as an example (if it is going through cmake)

#14967

Revert "Manually close the tree for https://github.com/flutter/flutter/issues/78567 (#78568)" (#78647)

This reverts commit 51dbc768.

This reverts commit 5e4e530e.