Sort the scripts and scenes into folders

main/ holds the main window and top bar, quiz/ the quiz and its parts,
player/ the music player, popups/ every popup and what they share, data/ the
songs, players, playlist and settings, server/ the MusicServer client,
common/ the list row and GameLog, and themes/ the themes and style boxes.

quiz/QuizToolbar.tscn

@@ -0,0 +1,45 @@
+[gd_scene format=3]
+
+[ext_resource type="Script" path="res://quiz/quiz_toolbar.gd" id="part_script"]
+
+[node name="QuizToolbar" type="Control" unique_id=1873301941]
+layout_mode = 3
+offset_right = 495.0
+offset_bottom = 31.0
+mouse_filter = 2
+script = ExtResource("part_script")
+
+[node name="ResetPlaylistButton" type="Button" parent="." unique_id=1754155620]
+layout_mode = 0
+offset_right = 111.0
+offset_bottom = 31.0
+focus_mode = 0
+action_mode = 0
+text = "Reset playlist"
+
+[node name="ResetPointsButton" type="Button" parent="." unique_id=942880776]
+layout_mode = 0
+offset_left = 128.0
+offset_right = 239.0
+offset_bottom = 31.0
+focus_mode = 0
+action_mode = 0
+text = "Reset points"
+
+[node name="SettingsButton" type="Button" parent="." unique_id=1193400323]
+layout_mode = 0
+offset_left = 256.0
+offset_right = 367.0
+offset_bottom = 31.0
+focus_mode = 0
+action_mode = 0
+text = "Settings"
+
+[node name="SoundTestButton" type="Button" parent="." unique_id=1332971879]
+layout_mode = 0
+offset_left = 384.0
+offset_right = 495.0
+offset_bottom = 31.0
+focus_mode = 0
+action_mode = 0
+text = "Sound test"