bug fixes and enhancements
1. added storageDisksDS, storageDisksTreeDS to globalObj datasource for tenant storage disks and disks tree.
2. dataview for disks grid, disks scatter chart and disks tree are now populated from storageDisksDS, storageDisksTreeDs.
3. moved and refactored parse and helper functions to tenant_monitor_storage_utils.js
4. fixed issue with individual diskActivity charts.
    1. hash change needs to be triggered only when disk drill down from the infra storage node details.
    2. clean up disk timer for exisiting activity fetches
    3. refresh disk chart views only if they are initialized.