Add achievement system with unlock and UI popup functionality (#8)

objects/ui/achievement_popup.tscn

@@ -0,0 +1,80 @@
+[gd_scene load_steps=4 format=3 uid="uid://tgaadui3lvdc"]
+
+[ext_resource type="Script" uid="uid://cejjan582nhfn" path="res://scripts/UI/AchievementPopup.cs" id="1_8pd1y"]
+[ext_resource type="Texture2D" uid="uid://cebeyr4wnibvk" path="res://sprites/achievement.png" id="2_1wq1d"]
+
+[sub_resource type="StyleBoxFlat" id="StyleBoxFlat_enx8n"]
+bg_color = Color(0, 0, 0, 1)
+
+[node name="AchievementPopup" type="CanvasLayer" node_paths=PackedStringArray("TitleLabel", "DescriptionLabel", "IconRect")]
+script = ExtResource("1_8pd1y")
+TitleLabel = NodePath("Container/Panel/MarginContainer/VBoxContainer/Title")
+DescriptionLabel = NodePath("Container/Panel/MarginContainer/VBoxContainer/Description")
+IconRect = NodePath("Container/Panel/MarginContainer/VBoxContainer/TextureRect")
+metadata/_custom_type_script = "uid://cejjan582nhfn"
+
+[node name="Container" type="Control" parent="."]
+custom_minimum_size = Vector2(200, 120)
+layout_mode = 3
+anchors_preset = 3
+anchor_left = 1.0
+anchor_top = 1.0
+anchor_right = 1.0
+anchor_bottom = 1.0
+offset_left = -200.0
+offset_top = -120.0
+grow_horizontal = 0
+grow_vertical = 0
+
+[node name="Panel" type="Panel" parent="Container"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+theme_override_styles/panel = SubResource("StyleBoxFlat_enx8n")
+
+[node name="MarginContainer" type="MarginContainer" parent="Container/Panel"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+theme_override_constants/margin_left = 4
+theme_override_constants/margin_top = 4
+theme_override_constants/margin_right = 4
+theme_override_constants/margin_bottom = 4
+
+[node name="VBoxContainer" type="VBoxContainer" parent="Container/Panel/MarginContainer"]
+layout_mode = 2
+
+[node name="Title" type="Label" parent="Container/Panel/MarginContainer/VBoxContainer"]
+custom_minimum_size = Vector2(120, 30)
+layout_mode = 2
+theme_override_font_sizes/font_size = 16
+text = "saaaaaaaaaaaaaaaaaaa"
+autowrap_mode = 3
+
+[node name="Description" type="Label" parent="Container/Panel/MarginContainer/VBoxContainer"]
+custom_minimum_size = Vector2(120, 40)
+layout_mode = 2
+theme_override_colors/font_color = Color(0.7, 0.7, 0.7, 1)
+text = "aaaaaaaaaaaaaaaaa"
+autowrap_mode = 3
+
+[node name="Control" type="Control" parent="Container/Panel/MarginContainer/VBoxContainer"]
+visible = false
+layout_mode = 2
+size_flags_vertical = 3
+
+[node name="TextureRect" type="TextureRect" parent="Container/Panel/MarginContainer/VBoxContainer"]
+visible = false
+custom_minimum_size = Vector2(128, 32)
+layout_mode = 2
+size_flags_horizontal = 4
+size_flags_vertical = 8
+texture = ExtResource("2_1wq1d")
+expand_mode = 4
+stretch_mode = 5