[MOV] howto/rdtraining: move "Getting started" to the tutorials dir

This commit also replaces references to the "Building a module"
tutorial by references to the "Getting started" tutorial.

task-2991663

Part-of: odoo/documentation#3655

content/developer/tutorials/getting_started/01_architecture.rst

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+.. _tutorials/getting_started/01_architecture:
+
+================================
+Chapter 1: Architecture Overview
+================================
+
+Multitier application
+=====================
+
+Odoo follows a `multitier architecture`_, meaning that the presentation, the business
+logic and the data storage are separated. More specifically, it uses a three-tier architecture
+(image from Wikipedia):
+
+.. image:: 01_architecture/three_tier.svg
+    :align: center
+    :alt: Three-tier architecture
+
+The presentation tier is a combination of HTML5, JavaScript and CSS. The logic tier is exclusively
+written in Python, while the data tier only supports PostgreSQL as an RDBMS.
+
+Depending on the scope of your module, Odoo development can be done in any of these tiers.
+Therefore, before going any further, it may be a good idea to refresh your memory if you don't have
+an intermediate level in these topics.
+
+In order to go through this tutorial, you will need a very basic knowledge of HTML and an intermediate
+level of Python. Advanced topics will require more knowledge in the other subjects. There are
+plenty of tutorials freely accessible, so we cannot recommend one over another since it depends
+on your background.
+
+For reference this is the official `Python tutorial`_.
+
+.. note::
+  Since version 15.0, Odoo is actively transitioning to using its own in-house developed `OWL
+  framework <https://odoo.github.io/owl/>`_ as part of its presentation tier. The legacy JavaScript
+  framework is still supported but will be deprecated over time. This will be discussed further in
+  advanced topics.
+
+Odoo modules
+============
+
+Both server and client extensions are packaged as *modules* which are
+optionally loaded in a *database*. A module is a collection of functions and data that target a
+single purpose.
+
+Odoo modules can either add brand new business logic to an Odoo system or
+alter and extend existing business logic. One module can be created to add your
+country's accounting rules to Odoo's generic accounting support, while
+a different module can add support for real-time visualisation of a bus fleet.
+
+Everything in Odoo starts and ends with modules.
+
+Terminology: developers group their business features in Odoo *modules*. The main user-facing
+modules are flagged and exposed as *Apps*, but a majority of the modules aren't Apps. *Modules*
+may also be referred to as *addons* and the directories where the Odoo server finds them
+form the ``addons_path``.
+
+Composition of a module
+-----------------------
+
+An Odoo module **can** contain a number of elements:
+
+:ref:`Business objects <reference/orm>`
+    A business object (e.g. an invoice) is declared as a Python class. The fields defined in
+    these classes are automatically mapped to database columns thanks to the
+    :abbr:`ORM (Object-Relational Mapping)` layer.
+
+:ref:`Object views <reference/views>`
+    Define UI display
+
+:ref:`Data files <reference/data>`
+    XML or CSV files declaring the model data:
+
+    * :ref:`views <reference/views>` or :ref:`reports <reference/reports>`,
+    * configuration data (modules parametrization, :ref:`security rules <reference/security>`),
+    * demonstration data
+    * and more
+
+:ref:`Web controllers <reference/controllers>`
+    Handle requests from web browsers
+
+Static web data
+    Images, CSS or JavaScript files used by the web interface or website
+
+None of these elements are mandatory. Some modules may only add data files (e.g. country-specific
+accounting configuration), while others may only add business objects. During this training, we will
+create business objects, object views and data files.
+:ref:`Web controllers <tutorials/getting_started/G_website>` and
+:ref:`static web data <tutorials/getting_started/I_jswidget>` are advanced topics.
+
+Module structure
+----------------
+
+Each module is a directory within a *module directory*. Module directories
+are specified by using the :option:`--addons-path <odoo-bin --addons-path>`
+option.
+
+An Odoo module is declared by its :ref:`manifest <reference/module/manifest>`.
+
+When an Odoo module includes business objects (i.e. Python files), they are organized as a
+`Python package <https://docs.python.org/3/tutorial/modules.html#packages>`_
+with a ``__init__.py`` file. This file contains import instructions for various Python
+files in the module.
+
+Here is a simplified module directory:
+
+.. code-block:: bash
+
+    module
+    ├── models
+    │   ├── *.py
+    │   └── __init__.py
+    ├── data
+    │   └── *.xml
+    ├── __init__.py
+    └── __manifest__.py
+
+Odoo Editions
+=============
+
+Odoo is available in `two versions`_: Odoo Enterprise (licensed & shared sources) and Odoo Community
+(open-source). In addition to services such as support or upgrades, the Enterprise version provides extra
+functionalities to Odoo. From a technical point-of-view, these functionalities are simply
+new modules installed on top of the modules provided by the Community version.
+
+Ready to start? Before writing actual code, let's go to the :doc:`next chapter <02_setup>` to review
+the Odoo installation process. Even if Odoo is already running on your system, we strongly suggest
+you go through this chapter to make sure we start on the same page during the development of our new
+application.
+
+.. _multitier architecture:
+    https://en.wikipedia.org/wiki/Multitier_architecture
+
+.. _Python tutorial:
+    https://docs.python.org/3.7/tutorial/
+
+.. _two versions:
+    https://www.odoo.com/page/editions