Add water balance module

[MostafaGomaa93]

Closes #286

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.
• Code is written according to the guidelines.
• The checks by MISS_HIT style checker and
  linter, below the pull request, are
  successful (green).
• Documentation is available.
• Add changes to the changelog file under section Unreleased.
• Model runs successfully, see tests.
• Ask a meinatainer to re-generate exe file if matlab codes are changed. About how to create an exe file, see exe readme.