Add initial CODEOWNERS to UFS-Chem applications

[benkozi]

• Use https://github.com/orgs/ufs-community/teams/catchem-core-team as the main infrastructure approving group.
• All merges to main require two approvals from the core team.
• All merges to develop require one approval from the core team.

TODO:

• CATChem CODEOWNERS added
• CECE CODEOWNERS added