Clean up "devops" in product_stage field

What does this MR do and why?

Describe in detail what your merge request does and why.

• The product_stage field of the metric yml files should not have devops:: prepended, it should just be the stage name (ex: use create instead of devops::create).
• Several metrics were labeled with the stage "devops". This is not actually a stage. Since the group associated with the metrics was group::import, the stage was updated to manage.

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