Create Helm Chart from Static Manifests

[hswong3i]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR convert our static deployment manifests from deploy/kubernetes/* into Helm Charts under charts/*, by running a convert script under deploy/util/chart-releaser.sh.

Moreover, it handle the chart release with branch gh-pages, by integrate with https://github.com/helm/chart-releaser-action.

The sample helm repo could find from https://alvistack.github.io/kubernetes-csi-external-snapshotter/index.yaml, by:

helm repo add external-snapshotter https://alvistack.github.io/kubernetes-csi-external-snapshotter
helm repo update
helm search repo external-snapshotter

Before each stable tag release, maintainers only required to:

1. Run the ./deploy/util/chart-releaser.sh and update templates under charts/*/templates/*
2. Double confirm charts/*/values.yml with correct values, e.g. image tags
3. git add --all --force charts/* && git commit

Which issue(s) this PR fixes:
Fixes #551
Fixes #622
Fixes #751

Create Helm Chart from Static Manifests

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