Major update to the Contributors Guide section of the documentation

The Contributors Guide section of the documentation has been significantly updated to include:

• A proper landing page
• Setting up development environment
• Contributing to the codebase
• Contributing to the documentation
• Merge (pull) request
• About Us

Furthermore, the following pages have been removed due to minimal usage:

• Glossary
• TODO

Additionally:

• The Minterpy logo in the documentation now uses "Wordmark-color.png" instead of "minterpy-logo.png".
• pre-commits config file has been cleaned up to minimize automatic codebase modification.

There is no changes in the codebase itself.

This MR should resolve Issue #72 (closed) and part of the Minterpy documentation update sprint #178.