[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#2066

content/developer/misc/api/iap.rst

@@ -25,7 +25,7 @@ App Developer:
 Overview
 ========
 
-.. figure:: images/players.png
+.. figure:: iap/players.png
     :align: center
 
     The Players
@@ -40,7 +40,7 @@ Overview
       bridge/translator between an Odoo system and the actual service.
 
 
-.. figure:: images/credits.jpg
+.. figure:: iap/credits.jpg
     :align: center
 
     The Credits
@@ -67,7 +67,7 @@ Overview
 .. note:: In the following explanations we will ignore the External Service,
           they are just a detail of the service you provide.
 
-.. figure:: images/normal.png
+.. figure:: iap/normal.png
     :align: center
 
     'Normal' service flow
@@ -87,7 +87,7 @@ Overview
        been rendered, possibly (depending on the service) displaying or
        storing its results in the client's system.
 
-.. figure:: images/no-credit.png
+.. figure:: iap/no-credit.png
     :align: center
 
     Insufficient credits
@@ -174,16 +174,16 @@ The service has *seven* important fields:
   how you **use it, its relevance** to make your service work and inform the
   client on how they can **access, update or delete their personal information**.
 
-.. image:: images/menu.png
+.. image:: iap/menu.png
     :align: center
 
-.. image:: images/service_list.png
+.. image:: iap/service_list.png
     :align: center
 
-.. image:: images/creating_service.png
+.. image:: iap/creating_service.png
     :align: center
 
-.. image:: images/service_created.png
+.. image:: iap/service_created.png
     :align: center
 
 You can then create *credit packs* which clients can purchase in order to
@@ -214,7 +214,7 @@ A credit pack is essentially a product with five characteristics:
     pack to another.
 
 
-.. image:: images/package.png
+.. image:: iap/package.png
     :align: center
 
 .. _iap-odoo-app:
@@ -283,7 +283,7 @@ local value via your application and additional parts via a remote service.
         </record>
     </odoo>
 
-.. image:: images/button.png
+.. image:: iap/button.png
     :align: center
 
 We can now implement the action method/callback. This will *call our own
@@ -516,7 +516,7 @@ parameters we can use to make things clearer to the end-user.
 JSON-RPC2_ Transaction API
 ==========================
 
-.. image:: images/flow.png
+.. image:: iap/flow.png
     :align: center
 
 * The IAP transaction API does not require using Odoo when implementing your

content/developer/misc/api/odoo.rst

@@ -80,13 +80,13 @@ account (although they can not be used to log-in via the interface).
 In order to add a key to your account, simply go to your
 :guilabel:`Preferences` (or :guilabel:`My Profile`):
 
-.. image:: images/preferences.png
+.. image:: odoo/preferences.png
    :align: center
 
 then open the :guilabel:`Account Security` tab, and click
 :guilabel:`New API Key`:
 
-.. image:: images/account-security.png
+.. image:: odoo/account-security.png
    :align: center
 
 Input a description for the key, **this description should be as clear and
@@ -102,7 +102,7 @@ lost).
 Once you have keys configured on your account, they will appear above the
 :guilabel:`New API Key` button, and you will be able to delete them:
 
-.. image:: images/delete-key.png
+.. image:: odoo/delete-key.png
    :align: center
 
 **A deleted API key can not be undeleted or re-set**. You will have to generate