[MOV] content/*: move resource files into their related page's directory

Since odoo/documentation#903, the guideline for the location of new
resource (images, downloadable files, RST includes...) files is to place
those inside the directory of the RST page that references them.

For example, if `doc1.rst` has a reference to `image.png` and to
`download.zip`, the file structure should look like this:

├── parent_doc/
│     └── doc1/
│     │     └── image.png
│     │     └── download.zip
│     └── doc1.rst
│     └── doc2.rst
├── parent_doc.rst

Before this commit, most of the resource files were still located inside
'media' directories holding all the resource files referenced by RST
pages located at the same level as these directories. In the example
above, a single 'media' directory would hold all the resource files
referenced by both `doc1.rst` and `doc2.rst`. Doing so prevented us from
figuring out easily which resource file was referenced by which RST page
and, thus, lead to unused resource files piling up in the repository. It
also made it more complicated to define codeowners regex rules because a
team could not simply be assigned to `/some_page.*` but needed to be
assigned to both `/some_page\.rst` and to the location of 'media'.

In order to help new content writers figure out the guideline when
taking examples from other RST pages, this commit retroactively applies
the guideline to existing resource files and 'media' directories. The
left-over resource files that are not referenced by any RST page are
removed.

task-2497965

Part-of: odoo/documentation#2064

content/administration/odoo_sh/getting_started/online-editor.rst

@@ -12,7 +12,7 @@ The online editor allows you to edit the source code of your builds from a web b
 It also gives you the possibility to open terminals, Python consoles, Odoo Shell consoles and
 `Notebooks <https://jupyterlab.readthedocs.io/en/stable/user/notebook.html>`_.
 
-.. image:: ./media/interface-editor.png
+.. image:: online-editor/interface-editor.png
    :align: center
 
 You can access the editor of a build through
@@ -66,20 +66,20 @@ server is not a good practice.
 
 To open a file in the editor, just double-click on it in the file browser panel on the left.
 
-.. image:: ./media/interface-editor-open-file.png
+.. image:: online-editor/interface-editor-open-file.png
    :align: center
 
 You can then begin to make your changes. You can save your changes with the menu
 :menuselection:`File --> Save .. File` or by hitting the :kbd:`Ctrl+S` shortcut.
 
-.. image:: ./media/interface-editor-save-file.png
+.. image:: online-editor/interface-editor-save-file.png
    :align: center
 
 If you save a Python file which is under your Odoo server addons path,
 Odoo will detect it and reload automatically so your changes are reflected immediately,
 without having to restart the server manually.
 
-.. image:: ./media/interface-editor-automaticreload.gif
+.. image:: online-editor/interface-editor-automaticreload.gif
    :align: center
 
 However, if the change is a data stored in database, such as the label of a field, or a view,
@@ -88,7 +88,7 @@ You can update the module of the currently opened file by using the menu
 :menuselection:`Odoo --> Update current module`. Note that the file considered as currently opened
 is the file focused in the text editor, not the file highlighted in the file browser.
 
-.. image:: ./media/interface-editor-update-current-module.png
+.. image:: online-editor/interface-editor-update-current-module.png
    :align: center
 
 You can also open a terminal and execute the command:
@@ -118,7 +118,7 @@ In this last command,
 * <branch> must be replaced by the name of the branch to which you want to push the changes,
   most-likely the current branch if you work in a development build.
 
-.. image:: ./media/interface-editor-commit-push.png
+.. image:: online-editor/interface-editor-commit-push.png
    :align: center
 
 .. Note::
@@ -160,7 +160,7 @@ Thanks to this, you will be able to display objects in HTML.
 You can for instance display cells of a CSV file using
 `pandas <https://pandas.pydata.org/pandas-docs/stable/tutorials.html>`_.
 
-.. image:: ./media/interface-editor-console-python-read-csv.png
+.. image:: online-editor/interface-editor-console-python-read-csv.png
    :align: center
 
 You can also open an Odoo Shell console to play around
@@ -189,12 +189,12 @@ to easily display lists and dicts in a pretty way, using the
 `rich display <https://ipython.readthedocs.io/en/stable/config/integrating.html#rich-display>`_
 mentioned above.
 
-.. image:: ./media/interface-editor-console-odoo-pretty.png
+.. image:: online-editor/interface-editor-console-odoo-pretty.png
    :align: center
 
 You can also use
 `pandas <https://pandas.pydata.org/pandas-docs/stable/tutorials.html>`_
 to display graphs.
 
-.. image:: ./media/interface-editor-console-odoo-graph.png
+.. image:: online-editor/interface-editor-console-odoo-graph.png
   :align: center