[PM-19145] refactor organization service.import async (#5800)

* initial lift and shift

* extract function RemoveExistingExternalUsers

* Extract function RemoveExistingUsers()

* extract function OverwriteExisting()

* create new model for sync data

* extract add users to function, rename

* rename OrganizatinUserInvite for command, implement command

* implement command

* refactor groups logic

* fix imports

* remove old tests, fix imports

* fix namespace

* fix CommandResult useage

* tests wip

* wip

* wip

* remove redundant code, remove looping db call, refactor tests

* clean up

* remove looping db call with bulk method

* clean up

* remove orgId param to use id already in request

* change param

* cleanup params

* remove IReferenceEventService

* fix test

* fix tests

* cr feedback

* remove _timeProvider

* add xmldoc, refactor to make InviteOrganizationUsersCommand vNext instead of default

* switch back to command

* re-add old ImportAsync impl

* fix test

* add feature flag

* cleanup

* clean up

* fix tests

* wip

* wip

* add api integration tests for users WIP

* groups integration tests

* cleanup

* fix error from merging main

* fix tests

* cr feedback

* fix test

* fix test

src/Core/Constants.cs

@@ -113,6 +113,7 @@ public static class FeatureFlagKeys
     public const string ScimInviteUserOptimization = "pm-16811-optimize-invite-user-flow-to-fail-fast";
     public const string EventBasedOrganizationIntegrations = "event-based-organization-integrations";
     public const string SeparateCustomRolePermissions = "pm-19917-separate-custom-role-permissions";
+    public const string ImportAsyncRefactor = "pm-22583-refactor-import-async";
     public const string CreateDefaultLocation = "pm-19467-create-default-location";
 
     /* Auth Team */