Implement asynchronous transfer queues, thread guards on RenderingDevice. Add ubershaders and rework pipeline caches for Forward+ and Mobile.

- Implements asynchronous transfer queues from PR #87590.
- Adds ubershaders that can run with specialization constants specified as push constants.
- Pipelines with specialization constants can compile in the background.
- Added monitoring for pipeline compilations.
- Materials and shaders can now be created asynchronously on background threads.
- Meshes that are loaded on background threads can also compile pipelines as part of the loading process.

servers/rendering/renderer_rd/renderer_compositor_rd.h

@@ -129,6 +129,7 @@ public:
 	_ALWAYS_INLINE_ uint64_t get_frame_number() const { return frame; }
 	_ALWAYS_INLINE_ double get_frame_delta_time() const { return delta; }
 	_ALWAYS_INLINE_ double get_total_time() const { return time; }
+	_ALWAYS_INLINE_ bool can_create_resources_async() const { return true; }
 
 	static Error is_viable() {
 		return OK;