Add sshdconfig _purge=false support for regular keywords

[tgauth]

PR Summary

• renames clobber to purge in various locations
• adds sshdconfig set support with _purge: false for regular keywords
• refactors some of the existing code in set_sshd_config() by creating write_config_map_to_text(), a helper function in util.rs
• refactors writing the config file into 2 distinct parts: global config then match block(s), in order to simplify appending any added keyword(s) to the global config without needing to worry about insertion/order preservation
• adds Pester tests for set scenarios, including if sshd_config file does not exist - the file creation will be implicit for _purge: true but will result in an error for _purge: false since there would be no existing settings to preserve

[Copilot]

Pull request overview

This PR renames the _clobber parameter to _purge and implements support for _purge=false to preserve existing SSH daemon configuration settings while updating specific keywords. The implementation refactors configuration writing into a dedicated helper function and adds comprehensive test coverage for various set scenarios.

Changes:

• Renamed _clobber to _purge across all files for clearer semantics
• Implemented _purge=false support for regular (non-repeatable, non-multi-value) keywords
• Refactored config file writing logic by extracting write_config_map_to_text() helper function

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
resources/sshdconfig/tests/sshdconfig.set.tests.ps1	Updated all test cases to use _purge instead of _clobber; added comprehensive test cases for _purge=false scenarios including file existence checks, multi-value keyword restrictions, and various keyword update/preserve/remove operations
resources/sshdconfig/tests/sshdconfig.get.tests.ps1	Added test case for handling non-existent config files
resources/sshdconfig/src/util.rs	Refactored format_sshd_value() to be private; changed format_value_as_string() to return String instead of Result; added write_config_map_to_text() helper function; added file existence check in invoke_sshd_config_validation(); updated error handling to use new FileNotFound error type
resources/sshdconfig/src/set.rs	Implemented _purge=false logic that retrieves existing config, validates keywords are not repeatable/multi-value, and merges changes; updated to use new write_config_map_to_text() helper
resources/sshdconfig/src/inputs.rs	Renamed clobber field to purge in CommandInfo struct
resources/sshdconfig/src/error.rs	Added new FileNotFound error variant
resources/sshdconfig/locales/en-us.toml	Updated error messages: removed clobberFalseUnsupported, added fileNotFound, purgeFalseRequiresExistingFile, and purgeFalseUnsupported

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

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[SteveL-MSFT]

Is there a way to use SshdConfigValue here to check those properties instead of the contains() checks?