Saketh Kalaga

@amold1 The other maintainers and I are quite busy currently with some urgent work going on in [gardener/etcd-druid](https://github.com/gardener/etcd-druid). This PR currently looks good, I personally don't see too much value...

@shreyas-s-rao @ishan16696 @seshachalam-yv could you guys take a look whenever possible? The PR's quite simple. Docs have been added as well.

@amold1 I've received comments from other maintainers about the PR currently, and will be making those changes. Will push a commit to address them in a bit.

@amold1 thanks for your contribution. The PR was unfortunately stuck for a while due to higher priority tasks. Please feel free to contribute to [gardener/etcd-backup-restore](https://github.com/gardener/etcd-backup-restore) and the etcd operator [gardener/etcd-druid](https://github.com/gardener/etcd-druid)...

@amold1 We've finally released [`v0.29.0`](https://github.com/gardener/etcd-backup-restore/releases/tag/v0.29.0) of etcd-backup-restore. You can now use the image of etcd-backup-restore directly to make use of the feature you've contributed.

Dependency not present in `go.mod` anymore.

https://github.com/gardener/etcd-backup-restore/pull/892 brought web identity authentication for S3.