refactor: migrate MQTT Consumer thread pools to Spring-managed beans
- AbstractMqttConsumer: remove private executorService, use constructor injection
- MqttDynamicConsumer/MqttChargeStationConsumer: remove private core/write executors,
inject via @Qualifier from ExecutorConfig
- ExecutorConfig: add mqttCoreExecutor, mqttWriteExecutor, abstractConsumerExecutor
with destroyMethod="shutdown"
- VehicleSyncTask: refine scanKeys() exception handling, add per-record try-catch
in doUpdateSysCar() loop
- Remove unused jjwt 0.9.1 (CVE-2019-17195) and springfox-boot-starter 3.0.0 deps