* Revert reset feature.

* Set default dist alarm settings and make dist package setting files right.

* Support empty list.

* Manually trigger agent registration and write registration status to file

* Delete unused variables

* Code optimization, encapsulating some methods

* add clear DataCarrier function

* revert SkyWalkingAgent

* Optimize code and logic, including updating applicatin_id in unRegisterOperationNames

* Server end metadata loss notification

* Server end metadata loss notification

* fix file stream close and other problem

* revert to old

* fix some bug
Signed-off-by: NLiu-XinYuan <879928098@qq.com>

* fix some bugs in agent reset

* add close inputStream and fileChannel and fix some bug

* fixed some bugs

Remove collector.servers and collector.direct_servers, and add collector.backend_service setting. cc @ascrutae

* Allow use SkyWalking plugin to override service in Agent core.

* Fix CI.

* Remove duplicate plugin load.

* Add test cases for new plugin boot service machanism.

* Add mechanism to disable any or all plugins, Relate: #186