Moved graphics classes into own namespace, added unit testing with gtest

src/graphics/Image.hpp

@@ -0,0 +1,17 @@
+#include <pango/pangocairo.h>
+
+#include <cstdint>
+
+namespace ptprnt::graphics {
+class Image {
+   public:
+    Image();
+    ~Image();
+    uint8_t* getRaw();
+
+   private:
+    PangoLayout* mLayout;
+    PangoFontDescription* mFontDescription;
+    cairo_surface_t* mSurface;
+};
+}  // namespace ptprnt::graphics