### What is this PR for?

By using the Raft protocol, multiple Zeppelin-Server groups are built into a Zeppelin cluster, the cluster State Machine is maintained through the Raft protocol, and the services in the cluster are agreed upon. The Zeppelin-Server and Zeppelin-Interperter services and processes are stored in the Cluster MetaData. Metadata information;

### What type of PR is it?
[Feature]

### Todos
* [x] add raft algorithm atomix jar
* [x] add cluster state machine
* [x] add state machine query command
* [x] add state machine delete command
* [x] add state machine put command
* [x] Isolate the netty JAR package introduced by atomix

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-3610

### How should this be tested?
[CI pass](https://travis-ci.org/liuxunorg/zeppelin/builds/418742522)

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? Yes

Author: liuxunorg <33611720@qq.com>
Author: Jeff Zhang <zjffdu@gmail.com>

Closes apache#3183 from liuxunorg/ZEPPELIN-3610 and squashes the following commits:

c899b15 [liuxunorg] uncomment maven-dependency-plugin.
af728bd [liuxunorg] add more doc to explain this class's responsibility.
d268ee7 [Jeff Zhang] fix test (#2)
97f17ac [liuxunorg] Cluster Raft module design

…refused

### What is this PR for?
- an interpreter process refused to connect due to it abnormal stop , which eventually caused the remove paragraph operation to fail to complete when i try remove a paragraph.

### What type of PR is it?
- Bug Fix

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-4712

### Questions:
Does the licenses files need update? NO
Is there breaking changes for older versions? NO
Does this needs documentation? NO

Author: xiejiajun <xiejiajun02@163.com>
Author: xie-jia-jun <xiejiajun02@163.com>

Closes apache#3710 from xiejiajun/branch-0.9 and squashes the following commits:

9bb7341 [xiejiajun] Merge remote-tracking branch 'origin/branch-0.9' into branch-0.9
9bc5605 [xiejiajun] bug fix:  when we removing a paragraph , an interpreter process refused to connect due to it abnormal stop , which eventually caused the remove paragraph operation to fail to complete.
97d2714 [xie-jia-jun] Merge pull request #2 from apache/branch-0.9
9b3c744 [xiejiajun] added timeout for getting Thrift client to avoid situations where the interpreter may not be restarted when the interpreter process exits unexpectedly

(cherry picked from commit 3fdd8bb)
Signed-off-by: Jeff Zhang <zjffdu@apache.org>