feat: introduce metrics framework for different metrics backend

[MrCroxx]

What's changed and what's your intention?

Please explain IN DETAIL what the changes are in this PR and why they are needed. :D

foyer users use various metrics backends. After investigation, there isn't an easy-to-use unified metrics interface in Rust ecosystem for at least prometheus and otel for now.

This PR introduces a minimal unified metrics interface and proemtheus/otel implementations that meets foyer's needs.

Checklist

• I have written the necessary rustdoc comments
• I have added the necessary unit tests and integration tests
• I have passed make all (or make fast instead if the old tests are not modified) in my local environment.

Related issues or PRs (optional)

[codecov]

Codecov Report

Attention: Patch coverage is 88.13056% with 80 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
foyer-bench/src/exporter.rs	0.00%	37 Missing ⚠️
foyer-memory/src/cache.rs	60.97%	16 Missing ⚠️
foyer/src/hybrid/builder.rs	73.17%	11 Missing ⚠️
foyer-bench/src/main.rs	30.00%	7 Missing ⚠️
foyer-storage/src/device/monitor.rs	79.16%	5 Missing ⚠️
foyer/src/hybrid/cache.rs	80.95%	4 Missing ⚠️

Files with missing lines	Coverage Δ
foyer-common/src/metrics/model.rs	100.00% <100.00%> (ø)
foyer-common/src/metrics/registry/noop.rs	100.00% <100.00%> (ø)
foyer-common/src/metrics/registry/opentelemetry.rs	100.00% <100.00%> (ø)
foyer-common/src/metrics/registry/prometheus.rs	100.00% <100.00%> (ø)
foyer-memory/src/raw.rs	91.10% <100.00%> (+0.05%)	⬆️
foyer-storage/src/large/batch.rs	83.07% <ø> (ø)
foyer-storage/src/large/flusher.rs	86.31% <100.00%> (+0.14%)	⬆️
foyer-storage/src/large/generic.rs	89.13% <100.00%> (+0.27%)	⬆️
foyer-storage/src/large/reclaimer.rs	85.48% <ø> (ø)
foyer-storage/src/large/recover.rs	90.29% <ø> (ø)
... and 17 more

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