Storage parsing updates to support Artifactory 7.x.x

[mstansberry]

• Removed references to duplicated storageSummary key (removed in 7.x)
  • All values from storageSummary.* keys are present in top level json keys
  • Validated update against 5.11.7, 6.9.3, 6.13.0, 6.14.0,6.18.1,7.2.1, and7.3.2`
• Added edge-case handling for repo.Percentage where value = N/A on new deployments
• Added debug logging for UsedSpace/Percentage parsing errors