Create CODEOWNERS

Is your feature request related to a problem? Please describe.
Please create a Codeowners file to allow @jbkolze and myself @krowvin the same control / PR approval perms we had over

https://github.com/HydrologicEngineeringCenter/cwms-data-api-client-javascript

This will enable us to maintain this source without requiring the backend team also approve these changes.

Describe the solution you'd like

Suggest we make a team and use that for the codeowners file, not names directly.

Add all of the contents of the openapi generator for the javascript client to be approved/maintained by @jbkolze and @krowvin

Describe alternatives you've considered

• Maintain the previous repo mentioned above
• Make Brandon/Charles maintainers of CDA itself (not preferred to help sep concerns in a mono repo this large)

Additional context

https://github.com/USACE/cwms-data-api/issues/1177#issuecomment-3127388152

Start by reviewing the repository's CODEOWNERS conventions and identifying the contents of the OpenAPI Generator JavaScript client that need coverage. Confirm the appropriate team and repository path, then verify that the resulting CODEOWNERS entry assigns approval responsibility to that team for the client contents.