[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#2068

content/administration/odoo_sh/getting_started/settings.rst

@@ -8,7 +8,7 @@ Overview
 
 The settings allow you to manage the configuration of your project.
 
-.. image:: ./media/interface-settings.png
+.. image:: settings/interface-settings.png
    :align: center
 
 Project name
@@ -16,7 +16,7 @@ Project name
 
 The name of your project.
 
-.. image:: ./media/interface-settings-projectname.png
+.. image:: settings/interface-settings-projectname.png
    :align: center
 
 This defines the address that will be used to access your production database.
@@ -31,7 +31,7 @@ Collaborators
 
 Manage the Github users who can access your project.
 
-.. image:: ./media/interface-settings-collaborators.png
+.. image:: settings/interface-settings-collaborators.png
    :align: center
 
 There are two levels of users:
@@ -87,7 +87,7 @@ Public Access
 
 Allow public access to your development builds.
 
-.. image:: ./media/interface-settings-public.png
+.. image:: settings/interface-settings-public.png
    :align: center
 
 If activated, this option exposes the Builds page publicly, allowing visitors to connect to your development builds.
@@ -117,7 +117,7 @@ as submodules in your branches to allow Odoo.sh to download them.
   If you are looking on how to set up your submodules,
   instructions are available in the chapter :ref:`Submodules <odoosh-advanced-submodules>` of this documentation.
 
-.. image:: ./media/interface-settings-submodules.png
+.. image:: settings/interface-settings-submodules.png
    :align: center
 
 When a repository is private, it is not possible to publicly download its branches and revisions.
@@ -148,7 +148,7 @@ Storage Size
 
 This section shows the storage size used by your project.
 
-.. image:: ./media/interface-settings-storage.png
+.. image:: settings/interface-settings-storage.png
    :align: center
 
 Storage size is computed as follows:
@@ -170,7 +170,7 @@ Additional database workers can be configured here. More workers help increase t
 production database is able to handle. If you add more, it will automatically be synchronized
 with your subscription.
 
-.. image:: ./media/interface-settings-workers.png
+.. image:: settings/interface-settings-workers.png
    :align: center
 
 .. Warning::
@@ -185,7 +185,7 @@ Staging Branches
 Additional staging branches allow you to develop and test more features at the same time. If you
 add more, it will automatically be synchronized with your subscription.
 
-.. image:: ./media/interface-settings-staging-branches.png
+.. image:: settings/interface-settings-staging-branches.png
    :align: center
 
 Activation
@@ -193,5 +193,5 @@ Activation
 
 Shows the status of the project's activation. You can change the project's activation code if needed.
 
-.. image:: ./media/interface-settings-activation.png
+.. image:: settings/interface-settings-activation.png
    :align: center