Refactor application structure and initialize core components

I decided to rewrite the program taking into account the experience gained.

internal/application/setting/ffmpeg.go

@@ -0,0 +1,25 @@
+package setting
+
+func (s *setting) GetFFmpegPath() string {
+	return s.fyneApp.Preferences().String("ffmpegPath")
+}
+
+func (s *setting) SetFFmpegPath(path string) {
+	s.fyneApp.Preferences().SetString("ffmpegPath", path)
+}
+
+func (s *setting) GetFFprobePath() string {
+	return s.fyneApp.Preferences().String("ffprobePath")
+}
+
+func (s *setting) SetFFprobePath(path string) {
+	s.fyneApp.Preferences().SetString("ffprobePath", path)
+}
+
+func (s *setting) GetFFplayPath() string {
+	return s.fyneApp.Preferences().String("ffplayPath")
+}
+
+func (s *setting) SetFFplayPath(path string) {
+	s.fyneApp.Preferences().SetString("ffplayPath", path)
+}