Add precip snow and energy flux to bmi

[MostafaGomaa93]

Description

Closes #121

Checklist

• Add a reference to related issues.
• @mentions of the person or team responsible for reviewing proposed changes.
• This pull request has a descriptive title.
• Follow contributing guide.
• The checks, below the pull request, are successful (green).
• Add documentation.
• Add tests.
• Add changes to the changelog file under section Unreleased.
• If your changes are about BMI, make sure that your changes are compatible
  with the latest version of STEMMUS_SCOPE
  and its docker image.