Infra: Replace usage of Dependabot's reviewers with CODEOWNERS

[yeikel]

What changes did you make? (Give an overview)

The reviewers field in the dependabot.yml file will be removed soon. For more information, see this blog post.

This pull request removes the usage of the reviewers field and creates a CODEWNERS file instead

How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

A picture of a cute animal (not mandatory but encouraged)