Renderer: rewrite render scheduling (#8683)

This rewrites renderer scheduling. Occlusion is now unified in a new Pass type.

src/render/pass/FramebufferElement.hpp

@@ -0,0 +1,24 @@
+#pragma once
+#include "PassElement.hpp"
+
+class CFramebufferElement : public IPassElement {
+  public:
+    struct SFramebufferElementData {
+        bool    main          = true;
+        uint8_t framebufferID = 0;
+    };
+
+    CFramebufferElement(const SFramebufferElementData& data_);
+    virtual ~CFramebufferElement() = default;
+
+    virtual void        draw(const CRegion& damage);
+    virtual bool        needsLiveBlur();
+    virtual bool        needsPrecomputeBlur();
+
+    virtual const char* passName() {
+        return "CFramebufferElement";
+    }
+
+  private:
+    SFramebufferElementData data;
+};