Request for a standard CODEOWNERS file across all SDK Language Repositories. (#46391)

* added headers

* Sorted CODEOWNERS

* Update CODEOWNERS

* Update CODEOWNERS

* Moved Cognitive - Mgmt service to Management libraries

* Added a comment block outlining expected format

* Modified comment block to pass linting checks

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Co-authored-by: ReilleyMilne <[email protected]>
Co-authored-by: Michelle Ma <[email protected]>

Author: 3 people