PowerScale Replication: Failback, reprotect and improvements

[santhoshatdell]

Description

• Replication improvements: Replication on the PowerScale only needs a SyncIQ policy on the source side. Having policy on both source and target arrays made things complicated. So target side policy creation has been avoided and reworked existing actions and replication group status.
• Failback functionality has been implemented so that user can recover from failover state.
  • Both modes of failback are implemented (KEEP-SOURCE and KEEP-TARGET).
• Reprotect functionality has been implemented so that user can reprotect the target site after failover. Please note that if user wants to reprotect source site, he should run failback_discard_changes action.

GitHub Issues

List the GitHub issues impacted by this PR:

GitHub Issue #
dell/csm#558
dell/csm#532
dell/csm#573

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained at least 90% code coverage
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Backward compatibility is not broken

How Has This Been Tested?

All supported actions along with new failback and reprotect actions are tested. During the tests, RG status (isSource property), SyncIQ policy on PowerScale arrays and data on the source & target PVs were continuously monitored.
Create PV/RG, suspend, resume, sync, failover, failback discarding remote changes, unplanned failover, failback discarding local changes, reprotect, and delete PV/RG.
Repctl tool RG status output is attached for reference.
test repctl output.txt
UnitTest.log

[santhoshatdell]

Workflow failures are due to changes required in gopowerscale code. I will update this PR once the gopowerscale PR is merged.
service/replication.go:702:37: localIsiConfig.isiSvc.client.ModifyPolicy undefined (type *goisilon.Client has no field or method ModifyPolicy