Update logging docs

[gewarren]

Replaces #51382.

Fixes #40870.

• Moves all logging docs and snippets under a "logging" subfolder and updates all backlinks.
• Updates high performance logging doc to focus on source-generation instead of LoggerMessage.Define.

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📄 File	🔗 Preview link
docs/core/diagnostics/diagnostic-resource-monitoring.md	Resource monitoring
docs/core/diagnostics/index.md	Diagnostics in .NET
docs/core/diagnostics/logging-tracing.md	Logging and tracing - .NET
docs/core/diagnostics/metrics-strongly-typed.md	Source-generated metrics with strongly-typed tags
docs/core/diagnostics/observability-otlp-example.md	docs/core/diagnostics/observability-otlp-example
docs/core/diagnostics/observability-prgrja-example.md	Example: Use OpenTelemetry with Prometheus, Grafana, and Jaeger
docs/core/diagnostics/observability-with-otel.md	.NET Observability with OpenTelemetry
docs/core/extensions/generic-host.md	.NET Generic Host
docs/core/extensions/httpclient-factory.md	IHttpClientFactory with .NET
docs/core/extensions/localization.md	Localization in .NET
docs/core/extensions/logging/console-log-formatter.md	docs/core/extensions/logging/console-log-formatter
docs/core/extensions/logging/custom-provider.md	Implement a custom logging provider in .NET
docs/core/extensions/logging/high-performance-logging.md	High-performance logging
docs/core/extensions/logging/library-guidance.md	Logging guidance for .NET library authors
docs/core/extensions/logging/log-buffering.md	docs/core/extensions/logging/log-buffering
docs/core/extensions/logging/log-sampling.md	Log sampling in .NET
docs/core/extensions/logging/overview.md	Logging in C# and .NET
docs/core/extensions/logging/providers.md	Logging providers
docs/core/extensions/logging/source-generation.md	Compile-time logging source generation
docs/core/extensions/primitives.md	docs/core/extensions/primitives
docs/core/extensions/windows-service.md	Create Windows Service using BackgroundService
docs/core/whats-new/dotnet-6.md	What's new in .NET 6
docs/fundamentals/code-analysis/quality-rules/ca1848.md	CA1848: Use the LoggerMessage delegates
docs/fundamentals/code-analysis/quality-rules/ca1873.md	CA1873: Avoid potentially expensive logging
docs/fundamentals/code-analysis/quality-rules/ca2023.md	docs/fundamentals/code-analysis/quality-rules/ca2023
docs/fundamentals/code-analysis/quality-rules/ca2254.md	CA2254: Template should be a static expression
docs/fundamentals/syslib-diagnostics/syslib1027.md	SYSLIB1027 error
docs/fundamentals/toc.yml	docs/fundamentals/toc
docs/orleans/host/monitoring/index.md	Orleans observability
docs/standard/runtime-libraries-overview.md	Runtime libraries overview