Enable e2e tests using emulators for cloud providers [ aws, gcp, azure ]

[anveshreddy18]

What this PR does / why we need it:

This PR enables e2e tests ( cluster based tests ) to be run with the emulators of 3 major cloud providers i.e AWS, GCP, AZURE. And of course can be run with the real infra as well. The reason for using emulators is to reduce the cost of using real infra every time a PR is raised because with the enablement of e2e tests with this PR, these tests will be run as prow job for every PR.

This PR also partially updates the outdated charts to reflect the changes made to the backup-restore over the years. This will help the users with setting up backup-restore effortlessly and also helps the developers with testing etcdbr standalone

Which issue(s) this PR fixes:
Fixes #722

Special notes for your reviewer:

Release note:

Enable e2e tests with cloud provider emulators and update helm charts for latest version of `etcdbr` to be used with etcd-wrapper

[gardener-robot]

@anveshreddy18 You need rebase this pull request with latest master branch. Please check.

[gitguardian]

⚠️ GitGuardian has uncovered 2 secrets following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secrets in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
-		RSA Private Key	5454c29	hack/e2e-test/infrastructure/kind/kubeconfig	View secret
-		RSA Private Key	dd4a097	hack/e2e-test/infrastructure/kind/kubeconfig	View secret

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2. Replace and store your secrets safely. Learn here the best practices.
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To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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