Refactoring TF operator code

[johnugeorge]

This PR tracks the refactoring of TF Operator code for separating common code. The code has been restructured into multiple packages.

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This change is 

[TravisBuddy]

Travis tests have failed

Hey @johnugeorge,
Please read the following log in order to understand the failure reason.
It'll be awesome if you fix what's wrong and commit the changes.

2nd Build

gometalinter --config=linter_config.json --vendor ./...

pkg/controller.v2/controller_logger.go:1::warning: file is not goimported (goimports)
pkg/controller.v2/jobcontroller.go:1::warning: file is not goimported (goimports)

3rd Build

gometalinter --config=linter_config.json --vendor ./...

pkg/controller.v2/controller_logger.go:1::warning: file is not goimported (goimports)
pkg/controller.v2/jobcontroller.go:1::warning: file is not goimported (goimports)

travis_time:end:1554f8db:start=1533146387495504523,finish=1533146532437841752,duration=144942337229

[coveralls]

Coverage increased (+0.7%) to 58.151% when pulling 25b110c on johnugeorge:refactor into 90259e7 on kubeflow:master.

[jlewi]

/assign @ankushagarwal

[gaocegege]

Generally LGTM

[gaocegege]

Do you want to use the logger? Then I think we could put the code in a separate package.

[johnugeorge]

@jlewi @gaocegege Changes are complete now. Can you review it now ?

[ankushagarwal]

/lgtm

@jlewi @gaocegege Can you of you approve? I don't have permissions.

[gaocegege]

/approve

@johnugeorge

Thanks for your awesome contribution! Hope we should share more implementation in the future.

[k8s-ci-robot]

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