[NEW] backup feature to gcs

[prateekn]

The problem/use-case that the feature addresses

Current backup option only supports aws s3, can we please have this feature for gcp gcs also.

Description of the feature

Built in backup option to gcs object store.

Alternatives you've considered

We tested a side-car solution, but would be great if its supported by keydb just like current aws s3 support.