feature(lint): use prettier and lint-staged for frontend javascript code

[jimexist]

See #244 for a consistent auto-reformat of current code

This change is 

[k8s-ci-robot]

Hi @jimexist. Thanks for your PR.

I'm waiting for a kubernetes or tensorflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[coveralls]

Coverage increased (+0.1%) to 37.915% when pulling a61caa5 on Jimexist:master into bcfc14f on tensorflow:master.

[coveralls]

Coverage remained the same at 37.782% when pulling a61caa5 on Jimexist:master into bcfc14f on tensorflow:master.

[coveralls]

Coverage remained the same at 37.782% when pulling a61caa5 on Jimexist:master into bcfc14f on tensorflow:master.

[zjj2wry]

/ok-to-test

[jimexist]

this PR needs @wbuchwalter 's attention, happy holiday by the way.

[coveralls]

Coverage remained the same at 37.782% when pulling b38069f on Jimexist:master into bcfc14f on tensorflow:master.

[jimexist]

/retest

[jlewi]

Test failed because it wasn't able to create the test cluster because we ran out of quota

[2017-12-25 15:25:44,772] {base_task_runner.py:98} INFO - Subtask: googleapiclient.errors.HttpError: <HttpError 403 when requesting https://container.googleapis.com/v1/projects/mlkube-testing/zones/us-east1-d/clusters?alt=json returned "Insufficient regional quota to satisfy request for resource: "IN_USE_ADDRESSES". The request requires '1.0' and is short '1.0'. The regional quota is '8.0' with '0.0' available.">

This is #80 (E2E tests leaking clusters)

[jlewi]

/test all

[jimexist]

@jlewi thanks.

still need @wbuchwalter's LGTM if possible

[jimexist]

since there's another PR that's depending on this and it is more of a dramatic change so i'll suggest merging this and there's always room to do reset.