Story (Required)

The goal of this story is rewrite the `setManagedSourceNamespaces` function present in argocd_controller in order to account for architectural changes in the operator conducted as part of other stories in this epic 

Background (Required)

The `setManagedSourceNamesapces` function is responsible for setting the list of managed source namespaces for a given Argo CD instance. However, there are some problems with the current implementation of it. 
At the beginning of the reconciliation cycle, the current logic only pulls the list of all labeled namespaces currently on the cluster and defers syncing the actual list of labelled namespaces vs what is expressed in .spec.sourceNamespaces during role reconciliation. There is also some namespace manipulation with deletion/addition of labels to namespaces etc happening during role reconciliation, which goes against the package responsibility philosophy we are trying to implement with the redesign.

The operator also does not check if a given argo-cd instance is cluster scoped or not before enabling apps-in-any-namespaces

Out of scope

any changes to how the feature works externally

Approach (Required)

Change logic in setSourceNamespaces such that existing and desired source namespace lists are reconciled and brought in sync entirely within the scope of this function. Also add a check to see if the instance is cluster scoped before setting the final list of source namespaces

Add kuttl tests to verify that no external changes in behavior occur as a result of this internal code shuffle 

Dependencies

none

Acceptance Criteria (Mandatory)

• unit tests added to verify function behaviour 

INVEST Checklist

Dependencies identified

Blockers noted and expected delivery timelines set

Design is implementable

Acceptance criteria agreed upon

Story estimated

Legend

Unknown

Verified

Unsatisfied

Done Checklist

• Code is completed, reviewed, documented and checked in
• Unit and integration test automation have been delivered and running cleanly in continuous integration/staging/canary environment
• Continuous Delivery pipeline(s) is able to proceed with new code included
• Customer facing documentation, API docs etc. are produced/updated, reviewed and published
• Acceptance criteria are met