[ZEPPELIN-4216]. Introduce ZEPPELIN_SERVER_IP to specify the ip address of thrift server

[zjffdu]

What is this PR for?

This PR use introduce env ZEPPELIN_SERVER_IP to specify the ip address of thrift server. It is used when you are in a complex network environment where yo might have multiple network cards or you use proxy. If it is not specified, it would still use the old approach to choose one IP randomly.

What type of PR is it?

[ Improvement ]

Todos

• - Task

What is the Jira issue?

• https://jira.apache.org/jira/browse/ZEPPELIN-4216

How should this be tested?

• CI pass

Screenshots (if appropriate)

Questions:

• Does the licenses files need update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[zjffdu]

@liuxunorg Could you help review it ? Thanks

[xunliu]

findAvailableHostAddress() Especially in a container environment, Different network types may not be able to get the correct IP address.
I think this PR can solve this problem.

LGTM