Implement anchor and fix bugs with rigid body (#27)

Co-authored-by: Eric NGUYEN <enguyen@techform.fr>
Reviewed-on: https://git.siklos-chaneru.duckdns.org/Siklos/svg-layout-designer-react/pulls/27

src/Components/Properties/Properties.test.tsx

@@ -23,7 +23,8 @@ describe.concurrent('Properties', () => {
       parentId: 'parentId',
       x: 1,
       y: 1,
-      isRigidBody: false
+      isRigidBody: false,
+      isAnchor: false
     };
 
     const handleChange = vi.fn((key, value) => {