Add utility to combine STLs

[ktangsali]

Modulus Pull Request

Description

Adds a utility to combine STLs. Useful for aero model inference.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.
• [x] The CHANGELOG.md is up to date with these changes.
• [ ] An issue is linked to this pull request.

Dependencies