renderer: Explicit sync fixes (#7151)

Enables explicit sync by default for most platforms

`misc:no_direct_scanout` -> `render:direct_scanout`

src/helpers/sync/SyncReleaser.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <vector>
+#include <functional>
+#include "../memory/Memory.hpp"
+
+/*
+    A helper (inspired by KDE's KWin) that will release the timeline point in the dtor
+*/
+
+class CSyncTimeline;
+class CEGLSync;
+
+class CSyncReleaser {
+  public:
+    CSyncReleaser(WP<CSyncTimeline> timeline_, uint64_t point_);
+    ~CSyncReleaser();
+
+    // drops the releaser, will never signal anymore
+    void drop();
+
+    // wait for this gpu job to finish before releasing
+    void addReleaseSync(SP<CEGLSync> sync);
+
+  private:
+    WP<CSyncTimeline> timeline;
+    uint64_t          point = 0;
+    SP<CEGLSync>      sync;
+};