Add docs for backup pvc config support

[shubham-pampattiwar]

Thank you for contributing to Velero!

Related Issues: #7747 and #7700

Design PR: #7982

Implementation PR: #8109

Please indicate you've done the following:

• 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

All modified and coverable lines are covered by tests ✅

Project coverage is 59.02%. Comparing base (a9463ce) to head (d4e7d14).
Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8119   +/-   ##
=======================================
  Coverage   59.02%   59.02%           
=======================================
  Files         364      364           
  Lines       30272    30272           
=======================================
  Hits        17867    17867           
  Misses      10959    10959           
  Partials     1446     1446           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Lyndon-Li]

@shubham-pampattiwar

Since it is a part of the snapshot data movement, I suggest we add this doc to the existing snapshot data movement doc. As an example, the node affinity for snapshot data movement is in the section of Node Selection of the same doc.

Otherwise, I think we still need to add a section in the snapshot data movement and refer to this doc, which is more complicated.

[shubham-pampattiwar]

@shubham-pampattiwar

Since it is a part of the snapshot data movement, I suggest we add this doc to the existing snapshot data movement doc. As an example, the node affinity for snapshot data movement is in the section of Node Selection of the same doc.

Otherwise, I think we still need to add a section in the snapshot data movement and refer to this doc, which is more complicated.

@Lyndon-Li Added a section in CSI Data Movement doc and linked the document in the abstract of the section. PTAL !