Add thumbnails to link tooltips if available (#1664)

This feature is off by default and can be enabled in the settings with the "Show link thumbnail" setting. This feature also requires the "Show link info when hovering" setting to be enabled.

thumbnails support is only there for direct image links, twitch clips, and youtube links. can be expanded in the future in the /api repo

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/singletons/TooltipPreviewImage.hpp

@@ -9,6 +9,7 @@ class TooltipPreviewImage
 public:
     static TooltipPreviewImage &instance();
     void setImage(ImagePtr image);
+    void setImageScale(int w, int h);
 
     TooltipPreviewImage(const TooltipPreviewImage &) = delete;
 
@@ -17,6 +18,9 @@ private:
 
 private:
     ImagePtr image_ = nullptr;
+    int imageWidth_ = 0;
+    int imageHeight_ = 0;
+
     std::vector<pajlada::Signals::ScopedConnection> connections_;
 
     // attemptRefresh is set to true in case we want to preview an image that has not loaded yet (if pixmapOrLoad fails)