clean cooking minimal example

[giftsichone]

Closes # (if applicable).

Changes proposed in this Pull Request

This minimal clean cooking example uses pypsa to model the competition between electric cooking and cheap gas cooking for an off-grid house over 24-hour snapshot to meet the cooking demand . The off-grid house consists of a diesel generator, electric cooker, gas store, gas cooker, empty bio-pallet store, pallet cooker, a constant electric load, a variable cooking load, and a load shedding generator.

Checklist

• Code changes are sufficiently documented; i.e. new functions contain docstrings and further explanations may be given in doc.
• Unit tests for new features were added (if applicable).
• Newly introduced dependencies are added to environment.yaml, environment_docs.yaml and setup.py (if applicable).
• A note for the release notes doc/release_notes.rst of the upcoming release is included.
• I consent to the release of this PR's code under the MIT license.