Add helm charts for feast jobservice

[tsotnet]

What this PR does / why we need it: This PR adds Helm Chart for Feast Job Service. Tested locally on minikube.

[tsotnet]

@oavdeev thanks for the comments, I realized most of the clean up stuff and was cleaning up the diff. Didn't find an equivalent functionality of Phabricator's "Plan Changes" to not notify reviewers... Let me know if there's anything else left!

[woop]

Do we need to hardcode the GCP specific fields here still? I think we want to move away from this (if we support AWS)

[tsotnet]

@woop we should probably handle that in another PR to get this one unblocked.

• All services (core, serving, jupyter) have the gcp-specific fields, so we need to figure out the overall solution here, not just for job service
• Looks like for AWS @oavdeev wrote the terraform script that uses envOverrides to override some environment variables, and he won't need to hardcode any AWS-specific stuff. However, this approach can't be used readily, since we don't have terraform for GCP deployment & some of these gcp fields are used outside env variables right now. Therefore I don't have a clear alternative to move these variables to.
• It won't affect AWS deployment in the short term, so we can temporarily leave it here

Let me know what you think!

[woop]

Sure, lets go ahead with cleaning this up in another PR.

[feast-ci-bot]

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[woop]

/retest

[tsotnet]

/retest

[woop]

/retest