Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
This is an application analogous to WidgetGallery, in that it tests
various capabilities of LibGUI models. Right now it is pretty bare, but
as more work towards LibGUI models is done regarding persistent model
indices, more demos will be added.
