Add subpass sync support for layout transitions

Add additional source and dest mask bits for "from external" and "to
external" subpass dependencies (respectively) when intial and final
layouts cause implicit layout transitions.

This is a big hammer -- any transition in a given direction will create
a full barrier.  Attachment specific stage and access flags could be
used instead with additional logic to deduce the prior and intended
subsequent usages.

drivers/vulkan/rendering_device_vulkan.cpp

@@ -3218,6 +3218,18 @@ VkRenderPass RenderingDeviceVulkan::_render_pass_create(const Vector<AttachmentF
 		} else {
 			ERR_FAIL_V_MSG(VK_NULL_HANDLE, "Texture index " + itos(i) + " is neither color, depth stencil or resolve so it can't be used as attachment.");
 		}
+
+		// NOTE: Big Mallet Approach -- any layout transition causes a full barrier
+		if (reference.layout != description.initialLayout) {
+			// NOTE: this should be smarter based on the textures knowledge of it's previous role
+			dependency_from_external.srcStageMask |= VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
+			dependency_from_external.srcAccessMask |= VK_ACCESS_MEMORY_READ_BIT | VK_ACCESS_MEMORY_WRITE_BIT;
+		}
+		if (reference.layout != description.finalLayout) {
+			// NOTE: this should be smarter based on the textures knowledge of it's subsequent role
+			dependency_from_external.dstStageMask |= VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
+			dependency_from_external.dstAccessMask |= VK_ACCESS_MEMORY_READ_BIT | VK_ACCESS_MEMORY_WRITE_BIT;
+		}
 	}
 
 	ERR_FAIL_COND_V_MSG(depth_stencil_references.size() > 1, VK_NULL_HANDLE,