Add functionality to c14_control_material()

Currently it just calls `controller::control()`. But it could:

- [ ] Detect species and return it as a separate vector
- [ ] Detect other text and return it as a separate vector

Start by locating c14_control_material() and reviewing how it currently delegates to controller::control(). Determine from the existing function behavior and package conventions how species and other text should be separated into vectors, then verify that both requested outputs are returned distinctly.

Written by the indexing model from the issue text.