feat(docs): add MkDocs site and GitHub Pages deploy workflow

[karakayahuseyin]

This pull request adds comprehensive documentation for PyThrust, including quickstart guides, API reference, example workflows, and a full mathematical description of the calibration model. It also introduces a dedicated documentation build and deploy workflow using MkDocs and GitHub Pages, and updates the CI workflow and README to reflect the removal of the PyBaMM dependency and new documentation practices.

Documentation additions and improvements:

• Added a complete API reference (docs/api_reference.md), getting started guide (docs/getting_started.md), example walkthroughs (docs/examples.md), and a development/testing guide (docs/development.md). [1] [2] [3] [4]
• Overhauled the main documentation index and improved section navigation and visuals (docs/index.md).
• Rewrote the motor calibration documentation with clearer equations, variable definitions, and step-by-step descriptions (docs/motor_calibration.md).
• Fixed a typo in the motor database documentation (docs/databases.md).
• Added MathJax configuration for LaTeX rendering in documentation (docs/javascripts/mathjax.js).

Build and deployment automation:

• Added a Deploy Docs workflow to .github/workflows/docs.yml that builds and deploys the MkDocs site to GitHub Pages when documentation files change on main.
• Updated the development and CI instructions to include the docs extra and removed the unused pybamm dependency from the main CI workflow (.github/workflows/ci-cd.yml).

Other updates:

• Removed the PyBaMM battery simulation section and image from the README, reflecting the removal of the dependency.

These changes provide a robust, user-friendly documentation experience and streamline the build and deployment process for the PyThrust project.

Closes #4