Revamp quickstart for model development with ValidMind (#748)

We have revamped the quickstart experience for model developers to provide a user-friendly introduction to using ValidMind for documenting models. This update covers the basics of using ValidMind to develop models. It guides you through registering your first model, using the ValidMind Library to run tests and document a model, and then reviewing your generated model documentation on the ValidMind platform.

This quickstart is the first in a series of new user journeys. Stay tuned for our upcoming introductory guides on model validation and platform administration.