[IMP] tutorials/server_framework_101: rewrite the tutorial

[AntoineVDV]

The Server Framework 101 (formerly Getting Started) is generally seen as an interesting and rewarding tutorial, but also somewhat outdated and too limited for beginners in Odoo development, as it fails to introduce key concepts of the server framework (e.g., controllers, tests, etc.). The instructions are also too directive for the reader to try and search by themselves and learn from it.

With this commit, all of the content of the tutorial is rewritten while keeping the objective of building a real estate module. The setup guide for tutorials is also improved to ensure smoother onboarding for Odoo employees and community members alike.

task-3802536

[robodoo]

Pull request status dashboard.

[AntoineVDV]

Move actions back to their corresponding view's XML file.