Bugfixes in local stops entities

Fixes:

• config flow pygtfs issue when setting up/refreshing local stop entities
• coordinator backfired when a stop was not presented from the db, e.g. when no departures today
• incorrect display of trips 'today' with a departure time 'today' but which are actually 'tomorrow', addresses; #163

Feature:

• local stop entities that show 'tomorrow' departures now also show their realtime departures, if provided; before these were hardcoded as 'tomorrow'