Add rudimentary dialogue system.

dialogue.gd

@@ -0,0 +1,15 @@
+class_name Dialogue
+extends Control
+
+func show_text(text: String) -> Dialogue:
+	visible = true
+	$Panel/Text.text = "[font_size=28]%s" % text
+	return self
+
+func dismiss_after(secs: float) -> Dialogue:
+	await get_tree().create_timer(secs).timeout
+	return dismiss()
+
+func dismiss() -> Dialogue:
+	visible = false
+	return self