Add Drawable improvements & preparation for future features

* Add DrawableFactoryInterface
* Add universal Drawable factory class
* Add x/y setter methods to PointInterface
* Replace Point::class type hints by PointInterface::class

tests/Unit/Geometry/Factories/DrawableTest.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Intervention\Image\Tests\Unit\Geometry\Factories;
+
+use Intervention\Image\Geometry\Factories\BezierFactory;
+use Intervention\Image\Geometry\Factories\CircleFactory;
+use Intervention\Image\Geometry\Factories\Drawable;
+use Intervention\Image\Geometry\Factories\EllipseFactory;
+use Intervention\Image\Geometry\Factories\LineFactory;
+use Intervention\Image\Geometry\Factories\PolygonFactory;
+use Intervention\Image\Geometry\Factories\RectangleFactory;
+use Intervention\Image\Tests\BaseTestCase;
+
+final class DrawableTest extends BaseTestCase
+{
+    public function testBezier(): void
+    {
+        $this->assertInstanceOf(BezierFactory::class, Drawable::bezier());
+    }
+
+    public function testCircle(): void
+    {
+        $this->assertInstanceOf(CircleFactory::class, Drawable::circle());
+    }
+
+    public function testEllipse(): void
+    {
+        $this->assertInstanceOf(EllipseFactory::class, Drawable::ellipse());
+    }
+
+    public function testLine(): void
+    {
+        $this->assertInstanceOf(LineFactory::class, Drawable::line());
+    }
+
+    public function testPolygon(): void
+    {
+        $this->assertInstanceOf(PolygonFactory::class, Drawable::polygon());
+    }
+
+    public function testRectangle(): void
+    {
+        $this->assertInstanceOf(RectangleFactory::class, Drawable::rectangle());
+    }
+}