feat(cluster): extend backup configuration for volumesnapshot and plugin

[m4s-b3n]

Summary of Changes

New Backup Options

This pull request introduces two new backup options to the chart: volumeSnapshot and plugin. These options provide additional flexibility for configuring backups in the CloudNativePG operator.

Volume Snapshots

• Added support for volume snapshots as a backup method.
• Configurable parameters include:
  • className
  • walClassName
  • tablespaceClassName
  • snapshotOwnerReference
  • online
  • onlineConfiguration (with waitForArchive and immediateCheckpoint)

Plugin Backups

• Added support for plugin-based backups.
• Configurable parameters include:
  • name
  • parameters

Documentation Updates

• Updated the README.md and README.md.gotmpl files to include documentation for the new backup options.
• Provided examples for configuring volume snapshots and plugin backups.

Extended Tests

• Added new test cases to validate the functionality of the new backup options.
• Extended the existing test suite to cover scenarios involving volume snapshots and plugin backups.

[m4s-b3n]

@itay-grudev please rerun chainsaw tests as the failed one seems to be failed because of an image pull error

[m4s-b3n]

@itay-grudev anything else I can do here?

[itay-grudev]

No. Thanks a lot. I'll review it when I can. I apologize in advance if I delay you, I am just under a lot of pressure right now.

[m4s-b3n]

@itay-grudev pull request already got merge conflicts. do you resolve them on merge or do you require me to do this?

[m4s-b3n]

@itay-grudev solved the conflicts by rebasing main