Move /cluster/audit to /audit

[anjalshireesh]

Community Contribution License

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contributions to the project maintainers under the Apache 2 license.

Description

As the audit metrics are server level and not overall cluster level.

Motivation and Context

More meaningful metrics endpoints

How to test this PR?

curl "http://<endpoint>/minio/metrics/v3/audit"

should return the audit related metrics

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[donatello]

Why not group node level that is not resource/hw related under /node at top-level (like audit, webhook, etc)?