[IMP] reference/user_interface: reformat and clarify views reference

In particular, the following changes are made:
- Use the `class` and `attribute` admonitions along with custom
  attributes to define classes, views' root attributes, views'
  components, and attribute values. This allows re-using the responsive
  design that was made for reference lists, and getting rid of the
  previous implementation that relied on class attributes, which were not
  intended for this usage and reduce readability while hindering further
  contributions due to a lack of flexibility (no admonitions,
  sub-attributes...)
- Use definition lists to define view types to allow for clearer and
  longer descriptions.
- Rewrite and restructure the explanations when there is a lack clarity.
- Extract duplicated content to included RST files.
- Display SVG images into dedicated admonitions.
- Fix RST and English mistakes.
- Rename `view_architecture` to `view_architectures`, as it lists all
  existing architectures and doesn't describe "the architecture of a
  view".
- Replace underscores with hyphens in image file names to improve SEO.

task-3458320

closes #5237

Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

Author: AntoineVDV

content/developer/howtos/standalone_owl_application.rst

@@ -108,7 +108,7 @@ layout.
 ========================================
 
 Now that we have created our assets bundle, we need to create a
-:ref:`QWeb view<reference/view_architecture/qweb>` that uses that assets bundle.
+:ref:`QWeb view <reference/view_architectures/qweb>` that uses that assets bundle.
 
 .. code-block:: xml
 

content/developer/reference/backend/data.rst

@@ -236,7 +236,7 @@ Defines an ``ir.ui.menu`` record with a number of defaults and fallbacks:
 ``template``
 ------------
 
-Creates a :ref:`QWeb view <reference/view_architecture/qweb>` requiring only the ``arch``
+Creates a :ref:`QWeb view <reference/view_architectures/qweb>` requiring only the ``arch``
 section of the view, and allowing a few *optional* attributes:
 
 ``id``

content/developer/reference/external_api.rst

@@ -1112,7 +1112,7 @@ Provides information about Odoo models via its various fields.
     list of the model's fields through a :class:`~odoo.fields.One2many` to
     :ref:`reference/webservice/inspection/fields`
 ``view_ids``
-    :class:`~odoo.fields.One2many` to the :doc:`../reference/user_interface//view_architecture`
+    :class:`~odoo.fields.One2many` to the :doc:`../reference/user_interface/view_architectures`
     defined for the model
 ``access_ids``
     :class:`~odoo.fields.One2many` relation to the

content/developer/reference/frontend/qweb.rst

@@ -675,7 +675,7 @@ Request-based
 
 Most Python-side uses of QWeb are in controllers (and during HTTP requests),
 in which case templates stored in the database (as
-:ref:`views <reference/view_architecture/qweb>`) can be trivially rendered by calling
+:ref:`views <reference/view_architectures/qweb>`) can be trivially rendered by calling
 :meth:`odoo.http.HttpRequest.render`:
 
 .. code-block:: python

content/developer/reference/user_interface.rst

@@ -8,6 +8,6 @@ User interface
     :titlesonly:
 
     user_interface/view_records
-    user_interface/view_architecture
+    user_interface/view_architectures
     user_interface/scss_inheritance
     user_interface/icons

content/developer/reference/user_interface/icons.rst

@@ -1,5 +1,7 @@
 :hide-page-toc:
 
+.. _reference/user_interface/ui_icons:
+
 ========
 UI icons
 ========