Add the PV backup information design document.

[blackpiglet]

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Does your change fix a particular issue?

Fixes #(issue)
This design is used to add the design document to address these issues:
pv-backup-info

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• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file or added /kind changelog-not-required as a comment on this pull request.
• Updated the corresponding documentation in site/content/docs/main.

[codecov]

Codecov Report

Merging #6962 (23b9484) into main (b4fb2d9) will increase coverage by 0.33%.
Report is 59 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #6962      +/-   ##
==========================================
+ Coverage   60.80%   61.14%   +0.33%     
==========================================
  Files         250      252       +2     
  Lines       26652    26916     +264     
==========================================
+ Hits        16205    16457     +252     
+ Misses       9297     9295       -2     
- Partials     1150     1164      +14     

see 21 files with indirect coverage changes

[shubham-pampattiwar]

@blackpiglet Should this be CloudProviderSnapshotInfo / CloudStorageSnapshotInfo / ClusterStorageSnapshotInfo instead ?

[blackpiglet]

This does have a point. The Velero native snapshot is actually a cloud storage snapshot, but the Velero Native Snapshot is a widely used termination in the Velero code and document.
I think we should keep it consistent here.
But I will add more comments on the structure definition to explain what it actually does.

[shubham-pampattiwar]

As we are adding PodVolumeBackupInfo , Shouldn't the DataUploadInfo be added too ?

[blackpiglet]

The SnapshotDataMovementInfo covers the snapshot data movement information. That structure covers the DataUpload information.