py_st3m: expose app_ctx or bundle_path on application object
Right now it complicates code, see https://git.flow3r.garden/flow3r/flow3r-firmware/-/blob/main/python_payload/apps/clouds/init.py if we ignore that this code also makes the path work when running with mpremote run, the code could be changed so that the toplevel draw propagates the path - or even does the cloud drawing in-line in the toplevel draw for something simple thus just being ctx.image(self.bundle_path + '/cloud.png', .. )