User Story

As a user I want to ensure deleting my large source does not prevent me from adding the source back while the delete is in progress and also do not want the pending deleted source to continue to ingest data.

This is a follow up to COST-1113.

Backend Requirements

• Mark the provider active flag to False when pending_delete is set to True.  This will ensure that we stop ingesting data for this source.
• Make necessary changes so that a user can add the same some source (duplicate billing_source/authentication values) while the same source is pending deletion.  The sources UI does not indicate that a source is pending deletion so we should ensure that the user can re-add the source after they delete it.

Acceptance Criteria

• Provider is not active when the celery source delete task is queued.
• User can add the source back while the old source is still pending deletion.