Update pipeline permissions

[BeFunes]

Description

• Rename "config source" into "pipeline"
• Updated permission grid to match prod (= contributors can't edit triggers or pipelines)

Reasons

A link to a GitHub and/or JIRA issue (if applicable).
Otherwise, a brief sentence about why you made these changes.

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[BeFunes]

@rosieyohannan not urgent, but something I'm wondering is if it's confusing to jam "trigger build" and "Trigger re-run via the CircleCI web app" into the "triggers" category.
Maybe a new header "Triggering builds" would make the distinction easier to grasp?