Add more conditions for mergify config

[osterman]

what

• Check that PR is not a WIP when commenting
• Use explict and everywhere needed in anchors
• Delay 5 minutes since last update before welcoming
• Label stale pull requests
• Close stale pull requests 3 days after last update
• Use active voice
• Rename anchors to be more clear
• Use more anchors to make it easier to understand what everything means

why

• Some edge cases we encountered
• Make mergify less error prone

[mergify]

Important

Cloud Posse Engineering Team Review Required

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[hans-d]

minor, not blocking for merge