Draft: Robustness: locate binaries through `/usr/bin/env`

What does this MR do?

Locate binaries through /usr/bin/env <binary> instead of using absolute paths like /usr/bin/<binary>. This is needed on systems like NixOS on which binaries do not have a static path.

Changes to public APIs

None, afaik.

Author's checklist (required)

• If bugs have been solved, tests have been added (guidelines)
• A changelog entry has been added (guidelines)
• Newly added code is documented (guidelines)
• Newly added code has a style consistent with the rest of the repository
• Intermediate commits compile (use git rebase -i main if not)

Related issues