Update CODEOWNERS file as needed

[hdamker]

Problem description

No CODEOWNERS are yet set.

Expected action

Create a pull request against the CODEOWNERS file to set the initial code owner(s).

Additional context

The repository is set up without branch protection to allow the work with only one codeowner.

A Sandbox API Repository must have at least one Codeowner. If the Sandbox API Repository has two or more Codeowners the activation of branch protection rules is recommended.

To activate branch protection rules write a mail to [email protected]