Changed schedule start- and end-time to schedule start and duration

Localized display of schedule start-time and duration
Removed displaying scheduling settings if "APScheduler" is missing
Input check for start-time and duration

cps/tasks/database.py

@@ -31,6 +31,7 @@ class TaskReconnectDatabase(CalibreTask):
         self.listen_address = config.get_config_ipaddress()
         self.listen_port = config.config_port
 
+
     def run(self, worker_thread):
         address = self.listen_address if self.listen_address else 'localhost'
         port = self.listen_port if self.listen_port else 8083