Add missing poweroff app

modules/firmware_apps/poweroff.py

@@ -0,0 +1,34 @@
+import app
+from app_components.tokens import clear_background
+
+from app_components.dialog import YesNoDialog
+
+
+class PowerOff(app.App):
+    async def run(self, render_update):
+        # Render initial state
+        await render_update()
+
+        # Create a yes/no dialogue, add it to the overlays
+        dialog = YesNoDialog("Power off?", self)
+        self.overlays = [dialog]
+
+        # Wait for an answer from the dialogue, and if it was yes, randomise colour
+        if await dialog.run(render_update):
+            import machine
+            import bq25895
+
+            bq25895.bq25895(machine.I2C(7)).disconnect_battery()
+
+        # Remove the dialogue and re-render
+        self.overlays = []
+
+        while True:
+            await render_update()
+
+    def draw(self, ctx):
+        ctx.save()
+        clear_background(ctx)
+        ctx.restore()
+
+        self.draw_overlays(ctx)