Better receiver info for Ho26

A new procedure has been added to both sched_initi and postob which will check the focus platform position and adds a comment to the log saying which receiver this corresponds to. For AUSTRAL experiments, please make sure that this reports that the “S/X receiver is on axis”. You can cross-check the rxp values against the nominal receiver positions here. NB - if Hobart can't get a monitoring connection to the drive PC it will report the rxp values as 1000 mm. If this is the case, you should probably reboot the drive PC and restart the FS.