[cinder-csi-plugin][charts] Remove snapshot controller yamls

[ramineni]

What this PR does / why we need it:
cinder-csi-plugin charts repo hosts snapshot-controller yamls , not CRDs which are required to be deployed along with them which might confuse the users more. As snapshot-controller should be deployed independent of csi driver and its cluster level, we dont need to host/maintain the charts in this repo.

This PR is to remove the same from the repo. The documentation required to deploy the snapshot-controller is already in place pointing to the correct repo.https://github.com/kubernetes/cloud-provider-openstack/blob/master/docs/cinder-csi-plugin/features.md#volume-snapshots

Which issue this PR fixes(if applicable):
fixes #1698

Special notes for reviewers:

Release note:

NONE

[linux-foundation-easycla]

• ❌ - Anusha Ramineni The commit (2ebc2f1) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[ramineni]

/cc @jichenjc @lingxiankong

[lingxiankong]

Can you look at the EasyCLA and see if it could be fixed?

[ramineni]

Can you look at the EasyCLA and see if it could be fixed?

@lingxiankong EasyCLA is optional for kubernetes , kubernetes/test-infra#24381 .

[lingxiankong]

/lgtm

[ramineni]

@jichenjc PTAL

[jichenjc]

/approve

@ramineni do we need EasyCLA sign or it's false alert?

[k8s-ci-robot]

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[ramineni]

/approve

@ramineni do we need EasyCLA sign or it's false alert?

@jichenjc we dont need it , its ignored for kubernetes