Fix issue that skywalking-agent.jar include the google class  and exclude the proto files inside protobuf-java

This reverts commit c52686f8.

* add feign default http plugin
add test case for feign default http interceptor

* move feign and okhttp plugins to the parent moudle

add test case for okhttp interceptor

* add plugins for resin-3.x and resin-4.x 

Add “checkStyle.xml” and “codeStyle.xml” files, varify the code-style when “mvn compile” and CI. This is the initialized commit.

Fix compile issue. Add new rest-service Object: SegmentsMessage.java. It uses Gson(JsonAdapter) as serialize/deserialize tool.

Remove collector dependency from agent-module. We will use HTTP-restful-service. Remove unnecessary dependencies/shades on collector and agent sides. Fix CI issue.

2.Release the prototype of ‘TraceSegment’.