* Support metrics downsampling.

* Fixed a check style error.

* Add generate indicator and dispatcher about service topology but not test.

* Delete call type from service relation.

* Streaming analysis topology test success.

* Fixed the check style error.

* Buffer stream.

* Buffer file reader.

* Buffer library performance test and functional test successfully.

* Fixed the code merge mistake.

* SkyWalking's trace receiver implementation.

* SkyWalking's trace receiver implementation.

* Delete collector module.

Add a lot of documents. @peng-yongsheng @hanahmily . Also @hanahmily , the k8 cluster management document and deploy document need you to add.

* Register start up.

* Service inventory register test success.

* Storage and Persistence.

* Storage config.

* Fixed the CI failure.

# 1447
Use `GET /api/v1/watch/namespaces/{namespace}/pods` api to watch pod's
containerIp which help collector containers to discovery each other.

* Receiver, aggregate, server finished.

* Cluster module implementation finished.

* Add login filter

Username and password are stored in application.yml with
prefix "security.user"

* Modify startup script and add webapp.yml config file

* Update quick-start document for default login username/password

* Update deploy document for new webapp.yml config file

* Update license for new files.

Fix IPMC checks for releasing.