[MINOR] Refactoring Job and Paragraph

[jongyoul]

What is this PR for?

Job class has only two sub classes. I don't think we need Job abstraction class anymore, then I'll move all function of Job into Paragraph and InterpretJob. Paragraph is used into zeppelin-server and InterpretJob is done by remoteInterpreterServer. I think what we disconnect those two different classes is better to maintain each side of codes. This PR moves two variable - result and results - from Job to Paragraph in order to remove Job class. It also based on ZEPPELIN-1594(#1753), thus all reviewers click the last commit and review it.

What type of PR is it?

[Refactoring]

Todos

• - Moved these variables into Paragraph

What is the Jira issue?

N/A

How should this be tested?

All things are same as before

Screenshots (if appropriate)

N/A

Questions:

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

[jongyoul]

Failed tests: NotebookTest.testAbortParagraphStatusOnInterpreterRestart:760 expected:<ABORT> but was:<RUNNING>

This test passed in my local and all others passed.

[jongyoul]

I've rebased after merging #1753

[jongyoul]

Will merge it.