Create iced_widget subcrate and re-organize the whole codebase

graphics/src/geometry/path/arc.rs

@@ -1,5 +1,5 @@
 //! Build and draw curves.
-use crate::{Point, Vector};
+use iced_core::{Point, Vector};
 
 /// A segment of a differentiable curve.
 #[derive(Debug, Clone, Copy)]

graphics/src/geometry/path/builder.rs

@@ -1,5 +1,6 @@
 use crate::geometry::path::{arc, Arc, Path};
-use crate::{Point, Size};
+
+use iced_core::{Point, Size};
 
 use lyon_path::builder::{self, SvgPathBuilder};
 use lyon_path::geom;