Generator: UI pages to have Edit/View capability

[StenPetrov]

The workflow should be:
View mode --buttonEdit--> Edit Mode
Edit Mode --buttonSave--> ViewModel.Save()
Edit Mode --buttonCancel--> ViewModel.Load(ViewModel.Model)

CollectionPage should have
[+] button in the toolbar which will show a new page in edit mode
Swipe list actions to edit and delete

[StenPetrov]

Most are there now, except for ListView context actions (delete items from list)