Enable resources to return metadata

[SteveL-MSFT]

PR Summary

Enable resources to return _metadata object that gets populated into the resource metadata field. Reserved Microsoft.DSC property is ignored, but a warning message is emitted. Works for all operations.

Also some reordering of existing code to keep it in proper order.

PR Context

Fix #467

[Copilot]

Pull Request Overview

Enable resources to return a _metadata object that’s merged into the resource’s metadata field, ignoring any Microsoft.DSC entries (with a warning), and applied consistently across all operations.

• Add Metadata struct and CLI support in dsctest for emitting metadata
• Enhance configurator to extract _metadata into Resource*Result.metadata and emit warnings for reserved keys
• Introduce manifest, locale strings, and end-to-end tests for the new Test/Metadata resource

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tools/dsctest/src/metadata.rs	Define Metadata struct for CLI
tools/dsctest/src/main.rs	Register metadata subcommand and serialize metadata outputs
tools/dsctest/src/args.rs	Add Metadata variant to CLI args
tools/dsctest/metadata.dsc.resource.json	Add manifest for Test/Metadata resource
dsc_lib/src/configure/mod.rs	Extract _metadata and integrate into resource metadata
dsc_lib/locales/en-us.toml	Add messages for ignored Microsoft.DSC and invalid metadata
dsc/tests/dsc_metadata.tests.ps1	Add tests verifying metadata extraction and warning emission

Comments suppressed due to low confidence (2)

dsc/tests/dsc_metadata.tests.ps1:27

• [nitpick] Consider adding an assertion for metadata.count to ensure the count property is populated correctly as part of the metadata object.

        $out.results[0].metadata.myNumber | Should -Be 42

tools/dsctest/src/main.rs:134

• [nitpick] The loop variable i is ambiguous; consider renaming it (e.g., index) for better readability.

            for i in 0..count {