[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/applications/finance/accounting/others/analytic/timesheets.rst

@@ -19,20 +19,20 @@ First, install the three applications necessary to use this
 functionality, namely **Accounting**, **Sales** and **Timesheet**. Enter the apps
 module name and install them.
 
-.. image:: media/timesheets14.png  
+.. image:: timesheets/timesheets14.png  
    :align: center
 
-.. image:: media/timesheets05.png
+.. image:: timesheets/timesheets05.png
    :align: center
 
-.. image:: media/timesheets11.png
+.. image:: timesheets/timesheets11.png
    :align: center
 
 Next you will need to enable analytical accounting. To do so enter the
 **Accounting app**. Select :menuselection:`Configuration --> Settings` and tick the
 **Analytic accounting** option (see picture below)
 
-.. image:: media/timesheets06.png
+.. image:: timesheets/timesheets06.png
    :align: center
 
 Apply your changes.
@@ -48,7 +48,7 @@ On the employee sheet enter the **HR settings** tab. Here you are able to
 specify the **Timesheet Cost** of your employee. In this case Harry has a
 cost of 18 euros / hours. We will thus fill in 18 in this field.
 
-.. image:: media/timesheets07.png
+.. image:: timesheets/timesheets07.png
    :align: center
 
 .. note:: 
@@ -69,7 +69,7 @@ We thus need to create a **sales order** with a **service** product invoiced
 **based on time and material** and tracked by timesheets with **hours** as unit
 of measures.
 
-.. image:: media/timesheets03.png
+.. image:: timesheets/timesheets03.png
    :align: center
 
 For more information on how to create a sales order based on time and
@@ -81,7 +81,7 @@ is confirmed. Our employees will have to point to that account (in this
 case **SO002-Smith&Co**) in order to be able to invoice their hours (see
 picture below).
 
-.. image:: media/timesheets10.png
+.. image:: timesheets/timesheets10.png
    :align: center
 
 Fill in timesheet
@@ -94,7 +94,7 @@ Account** discussed above.
 
 Harry worked three hours on a SWOT analysis for Smith&Co.
 
-.. image:: media/timesheets01.png
+.. image:: timesheets/timesheets01.png
    :align: center
 
 In the meantime, Cedric discussed businesses needs with the customer for
@@ -104,7 +104,7 @@ well on the **Analytic Account**.
 In the **Sales Order** we notice that the delivered amounts of hours is
 automatically computed (see picture below).
 
-.. image:: media/timesheets02.png
+.. image:: timesheets/timesheets02.png
    :align: center
 
 Analytic accounting
@@ -128,13 +128,13 @@ Note : you can specify a period for **Analysis**. If you want to open the
 current situation you should keep the fields empty. We can already note
 the credit and debit balance of the account.
 
-.. image:: media/timesheets12.png
+.. image:: timesheets/timesheets12.png
    :align: center
 
 If we click on the account a special button is provided to have the
 details of cost and revenues (see picture below).
 
-.. image:: media/timesheets13.png
+.. image:: timesheets/timesheets13.png
    :align: center
 
 Click the button **Cost/Revenue** to have an overview of cost and revenues with the
@@ -152,18 +152,18 @@ In this menu we have several options to analyse the human resource cost.
    of the project. Add a custom **Filter** where the **Analytic Account**
    contains the **Sales Order** number.
 
-   .. image:: media/timesheets04.png
+   .. image:: timesheets/timesheets04.png
       :align: center
 
    In the results we see timesheets activities and invoiced lines with
    the corresponding costs and revenues.
 
-   .. image:: media/timesheets09.png
+   .. image:: timesheets/timesheets09.png
      :align: center
 
 2. We can group the different analytical accounts together and check
    their respective revenues. Simply group by **Analytic account** and
    select the **Graph view** to have a clear overview.
 
-   .. image:: media/timesheets08.png
+   .. image:: timesheets/timesheets08.png
       :align: center