Refactor relief rendering and generation logic

- Migrate relief icon rendering from SVG to WebGL for improved performance.
- Introduce a new relief generator module to handle relief icon creation.
- Update event listeners in relief editor to use a consistent `byId` method.
- Synchronize relief data with the current SVG DOM when exiting edit mode.
- Enhance relief icon management by integrating new utility functions for generating and resolving relief icons.
- Clean up legacy code and improve overall structure for better maintainability.

public/modules/ui/biomes-editor.js

@@ -323,7 +323,8 @@ function editBiomes() {
   }
 
   function regenerateIcons() {
-    drawReliefIcons();
+    pack.relief = [];
+    drawRelief();
     if (!layerIsOn("toggleRelief")) toggleRelief();
   }