Telemetry Frontend gRPC NBI Re-structuring
- Changed the column type of the start and end timestamps to Float. - Added ConvertRowToCollector() in TelemetryModel. - Renamed the class variable from "DBobj" to "tele_db_obj". - Renamed the local variable from "collector_id" to "collector_uuid". - Added PublishStopRequestOnKafka() to publish the stop collector request on Kafka. - Improved the test files.