Include several tests and minor fixes

[ricardoleal20]

Summary 📝

Added

• [Classifiers]: Add the classifiers for the project, including homepages and more stuff
• [Maturin]: Add information for the correct Rust/Python project be implemented
• [Tests]: Include the Engine and the solver tests
• [Variable]: Now, you can directly include the initial value of the variable in their definition
• [Variable]: Now, in the setter, the value set is going to be the closes bound if the expected value is outside the bound

Fixed

• [Engine]: The engine now it updates the value using the setting method value, instead of going directly for the _value.

Type of change 🦺

• 💥MAJOR CHANGE: Fix or feature that can alter the behavior of a component or project. Includes breaking changes.
• ✨MINOR CHANGE: Addition of new features or deprecation of existing ones, without breaking changes.
• 🩹PATCH CHANGE: Refactor of an existing component, bug fix, or improvement of a new library without breaking changes.

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How has this been tested? ⚗️

Includes new and improved tests

Checklist 📋

Ensure all the following points are satisfied before opening a Pull Request for review. If not, consider opening it as a draft.

• 💻 My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• ⚠️ My code doesn't generate new warnings or alerts.
• 🧪 New and existing tests pass successfully.
• ✅ The checks pass successfully on my local machine.
• 💯 My code is covered by tests.
• 📓 Documentation and comments are added where needed.