Updated external-snapshot-metadata sidecar support to its alpha level

[carlbraganza]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change
/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #594

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

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[PrasadG193]

Do you think its a good idea to summarize actions performed by the client behind the scene to give more clarity?

[carlbraganza]

It made a lot of sense before but now it repeats what is present in the external-snapshot-metadata repo and the documentation.