game: move ui stuff to own folder

scenes/managers/ui/player_ui.gd

@@ -0,0 +1,18 @@
+class_name PlayerUI
+extends Control
+
+@onready var hp_bar: ProgressBar = $CenterContainer/VBoxContainer/ProgressBar
+@onready var elapsed_label: Label = $CenterContainer/VBoxContainer/ElapsedLabel
+
+func set_hp(value: float):
+	hp_bar.value = value
+
+func set_elapsed_time(value: float):
+	elapsed_label.text = format_time(value)
+	
+func format_time(seconds: float) -> String:
+	var total_ms = int(seconds * 1000.0)
+	var s = (total_ms / 1000) % 60
+	var m = (total_ms / 60000)
+
+	return "%02d:%02d" % [m, s]