Refactor gameplay menus into owned scenes

ui/menus/GarrisonMenu.gd

@@ -0,0 +1,39 @@
+extends "res://ui/menus/ModalMenu.gd"
+
+@onready var panel: Control = $Panel
+@onready var status: Label = $StatusLabel
+
+var building_id: int = 0
+
+
+func _ready() -> void:
+	super._ready()
+	panel.changed.connect(refresh)
+
+
+func open_for(next_building_id: int) -> void:
+	building_id = next_building_id
+	panel.building_id = building_id
+	open_menu()
+	refresh()
+
+
+func close_menu() -> void:
+	super.close_menu()
+	building_id = 0
+	panel.building_id = 0
+
+
+func refresh() -> void:
+	if building_id == 0:
+		return
+	panel.building_id = building_id
+	panel.refresh()
+	var ordered: int = GameState.garrison_desired_total(building_id)
+	var crewed: int = GameState.garrison_crew(building_id).size()
+	if ordered == 0:
+		status.text = "No vessels ordered. Only armed vessels can hold a position."
+	elif crewed >= ordered:
+		status.text = "Garrison at full strength"
+	else:
+		status.text = "%d of %d berths crewed - vessels are sent from the mothership as they become available" % [crewed, ordered]