fix(metrics-collector): allow user to nuke ephemeral-storage requests

[khersey]

What this PR does / why we need it:

• Allows users to nuke ephemeral-storage request and limit by setting these values to something negative in the katib-config configmap.
• This fixes an issue where GKE node pools will not scale up because they are not compatible with any pod requesting ephemeral-storage (see linked issue for more details)

Which issue(s) this PR fixes:
Fixes #1289

Special notes for your reviewer:

1. First contribution and first time dabbling in Go so let me know if I am not conforming to best practices.
2. Please let me know if there is a better way/place to solve this problem within the codebase.

[kubeflow-bot]

This change is 

[k8s-ci-robot]

Hi @khersey. Thanks for your PR.

I'm waiting for a kubeflow 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.

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[andreyvelich]

Thank you for your contribution @khersey!
/ok-to-test

[andreyvelich]

/cc @gaocegege @johnugeorge

[gaocegege]

/retest

[andreyvelich]

@gaocegege Test will not work until we fix this problem: kubeflow/testing#749 (comment).
We should submit new project for test infra.
See this: kubeflow/community-infra#10

[andreyvelich]

@khersey Can you run gofmt, please?

[andreyvelich]

/retest

[andreyvelich]

I believe you also need to rebase to fix e2e tests.

[andreyvelich]

@khersey Thanks for the rebase.

Can you revert gofmt changes from api.pb.go files, please?
These files are generated automatically from GRPC APIs and we don't verify them in the script.

I will update update-gofmt to not fmt these files script in the separate PR.

[khersey]

@andreyvelich yeah sorry for the delay, will do. Looks like the frontend tests are failing, not sure that's related to my changes

[andreyvelich]

@andreyvelich yeah sorry for the delay, will do. Looks like the frontend tests are failing, not sure that's related to my changes

I believe we need to modify nvm version in Travis for frontend tests.
I fixed it in this PR: #1340.

[khersey]

@andreyvelich ok api.pb formatting changes have been nuked 💣

[andreyvelich]

/retest

[andreyvelich]

Thanks @khersey!
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andreyvelich

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