include bucket diagnostics

[juliasloan25]

Purpose

To facilitate debugging of AMIP simulations. We can use the existing diagnostics from ClimaLand - defined here for the bucket.

Content

• [x] update bucket_init to initialize diagnostics from ClimaLand
  • required interface change: pass artifacts directory to bucket_init
• [x] add ClimaDiagnostics to experiments/ClimaEarth environment

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• [ ] I have read and checked the items on the review checklist.