[orx-shapes] Add irregular grid support and demo examples

This commit introduces `Rectangle.irregularGrid`, enabling the creation of grids with irregular spacing based on weights. New helper methods and properties for 2D rectangle lists, such as subgrid selection, bounds calculation, and random access, are also added. Additionally, two new demos showcase regular and irregular grid features.

orx-shapes/src/jvmDemo/kotlin/primitives/DemoRectangleIrregularGrid.kt

@@ -0,0 +1,39 @@
+package primitives
+
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.extra.color.presets.CORAL
+import org.openrndr.extra.noise.uniform
+import org.openrndr.extra.noise.uniforms
+import org.openrndr.extra.shapes.primitives.column
+import org.openrndr.extra.shapes.primitives.irregularGrid
+import org.openrndr.extra.shapes.primitives.row
+import kotlin.random.Random
+
+fun main() = application {
+    configure {
+        width = 720
+        height = 720
+    }
+    program {
+        extend {
+            val r = Random(100)
+            val grid = drawer.bounds.irregularGrid(
+                Double.uniforms(13, 0.1, 0.5, r),
+                Double.uniforms(13, 0.1, 0.5, r),
+                20.0, 20.0
+            )
+
+            drawer.fill = null
+            drawer.stroke = ColorRGBa.WHITE
+            drawer.rectangles(grid.flatten())
+
+            drawer.stroke = ColorRGBa.BLACK
+            drawer.fill = ColorRGBa.PINK.opacify(0.5)
+            drawer.rectangles(grid.column(2))
+
+            drawer.fill = ColorRGBa.CORAL.opacify(0.5)
+            drawer.rectangles(grid.row(6))
+        }
+    }
+}