[FIX] developer: remove confusing section about starting services

When writing the documentation page for standalone Owl apps, it was
originally required to create the env and start the services manually,
and then mount the application by giving it a bunch of configuration
parameters. During review, it was noted that this was error prone and
confusing, and as such a corresponding PR added a helper to mount the
application without needing to do much by hand. While the code was
adapted in the documentation that was merged, the text still referred to
starting the services and creating the environment which is no longer
necessary.

This commit removes references to those things, and because the
resulting section is very small and not very interesting it has been
merged into the previous section.

closes odoo/documentation#6692

X-original-commit: 8e3008f06a
Signed-off-by: Samuel Degueldre (sad) <sad@odoo.com>

content/developer/howtos/standalone_owl_application.rst

@@ -12,7 +12,6 @@ Overview
 To have a standalone Owl app, a few things are required:
 
 - a root component for the application
-- some setup code to start the services and mount the component
 - an assets bundle that contains the setup code
 - a QWeb view that calls the assets bundle
 - a controller that renders the view
@@ -46,18 +45,8 @@ Then create the JavaScript file for that component in :file:`/your_module/static
         static props = {};
     }
 
-.. seealso::
-   :ref:`Owl components reference<frontend/components>`.
-
-2. Setting up the environment and mounting the application
-==========================================================
-
-An Owl application needs an environment, and the Odoo JavaScript framework needs that environment to
-contain the :ref:`services<frontend/services>`.
-Starting the services is also required to load the translations, which we need to do before mounting
-our Owl application, so that we can give Owl a working translation function.
-
-Create the JavaScript file that will mount the app in :file:`/your_module/static/src/standalone_app/app.js`.
+It's generally a good idea to have the application setup code that mounts the component in a separate
+file. Create the JavaScript file that will mount the app in :file:`/your_module/static/src/standalone_app/app.js`.
 
 .. code-block:: js
 
@@ -68,8 +57,16 @@ Create the JavaScript file that will mount the app in :file:`/your_module/static
 
     whenReady(() => mountComponent(Root, document.body));
 
+The `mountComponent` utility function will take care of creating the Owl application and configuring
+it correctly: it will create an environment, start the :ref:`services<frontend/services>`, make sure
+the app is translated and give the app access to the templates from your assets bundle, among other
+things.
 
-3. Creating an assets bundle containing our code
+.. seealso::
+   :ref:`Owl components reference<frontend/components>`.
+
+
+2. Creating an assets bundle containing our code
 ================================================
 
 In the manifest of your module, create a new :ref:`assets bundle<reference/assets_bundle>`.
@@ -107,7 +104,7 @@ layout.
 .. seealso::
     :ref:`Module manifest reference<reference/module/manifest>`.
 
-4. XML view that calls the assets bundle
+3. XML view that calls the assets bundle
 ========================================
 
 Now that we have created our assets bundle, we need to create a
@@ -143,7 +140,7 @@ should be an object that contains the following:
 - `__session_info__`, that contains information from the server that is always needed and for which
   we don't want to perform an additional request. More on this in the next section.
 
-5. Controller that renders the view
+4. Controller that renders the view
 ===================================
 
 Now that we have the view, we need to make it accessible to the user. For that purpose, we will create