* Sometimes add subscription pipe to group config will be executed before
bind adapter, the wrong pipe will be subscribe in group config. So we
wait for complete binding adapter and then add subscription pipe.
* Fix issue of failed to build with gcc 10.3.0
1. Variable array serialization and deserialization support
2. Variable basic data type setting
3. Variable export function unit test
4. Integrate MQTT and Variable
5. Delete the work queue in the MQTT driver
* Support these sync command in adapter.c
* Add some interface functions in neu_manager.c to support these command
* Add enum type of error code for neuron