Add utility methods for job reconciliation

[terrytangyuan]

This PR adds utility methods for job reconciliation (part of #7). Note that part of the code is commented out for now until service reconciliation logic is in place.

---

This change is 

[terrytangyuan]

@richardsliu Coverage/coveralls calculation does not seem correct (it says job_controller folder's coverage decreased but I see no file under this directory seems to have decreased coverage). Would we still be able to merge this PR (once approved) while coveralls check failed?

[terrytangyuan]

Thanks @richardsliu. Just updated so they are more readable now.

[gaocegege]

LGTM Is there anyone working on service reconciliation logic?

[terrytangyuan]

@gaocegege Yes someone from our team is putting together a PR (should be out soon).

[richardsliu]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: richardsliu

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [richardsliu]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment