Support custom universe domain

[mmohamed]

Fixe issues using private GCP :

• add support for universe domain for backup and volume snapshot
• Switch to client method for SignedURL call to inherit storage endpoint configuration
• Add compute.disks.setLabels required for restore volume from snapshot with labels

[codecov-commenter]

Codecov Report

❌ Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 27.83%. Comparing base (5e94ed2) to head (49dc137).

Files with missing lines	Patch %	Lines
velero-plugin-for-gcp/object_store.go	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #242      +/-   ##
==========================================
+ Coverage   27.39%   27.83%   +0.44%     
==========================================
  Files           4        4              
  Lines         595      449     -146     
==========================================
- Hits          163      125      -38     
+ Misses        420      312     -108     
  Partials       12       12              

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