[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/sales/point_of_sale/restaurant/restaurant.rst

@@ -17,14 +17,14 @@ To activate the bar/restaurant features, go to :menuselection:`Point of
 Sale --> Configuration --> Point of Sale` and open your PoS. Now,
 select *Is a Bar/Restaurant*.
 
-.. image:: media/restaurant_01.png
+.. image:: restaurant/restaurant_01.png
     :align: center
     :alt: Restaurant set up. Enabling the is a bar/Restaurant feature on a PoS
 
 New features are shown with a fork and a knife next to it, indicating
 that they are restaurant-specific.
 
-.. image:: media/restaurant_02.png
+.. image:: restaurant/restaurant_02.png
     :align: center
     :alt: Several restaurant features. Bill printing, bill splitting and tips
 
@@ -35,11 +35,11 @@ Once your *Point of Sale* has been configured, select *Table
 Management* under :menuselection:`Point of Sale --> Configuration -->
 Point of Sale`. Then, click on *Floors* to create and name your floor and tables.
 
-.. image:: media/restaurant_03.png
+.. image:: restaurant/restaurant_03.png
     :align: center
     :alt: View of the table management feature. Way to manage and create floors for a pos
 
-.. image:: media/restaurant_04.png
+.. image:: restaurant/restaurant_04.png
     :align: center
     :alt: Backend view of a restaurant floor. Table name and number of sits for each table
 
@@ -52,14 +52,14 @@ Add tables
 To add tables, you can also open your PoS interface to see your
 floor(s).
 
-.. image:: media/restaurant_05.png
+.. image:: restaurant/restaurant_05.png
     :align: center
     :alt: View of the floors menu to manage several floors at the same time
 
 Then, click on *Edit Mode* (pencil icon on the upper right corner) to be allowed to
 create, move, modify tables, etc.
 
-.. image:: media/restaurant_06.png
+.. image:: restaurant/restaurant_06.png
     :align: center
     :alt: View of the floor management. Add tables, the number of sits, their name and their shape
 
@@ -74,7 +74,7 @@ Register your table(s) orders
 To register an order, click on the respective table. By doing so, you are taken
 to your main interface.
 
-.. image:: media/restaurant_07.png
+.. image:: restaurant/restaurant_07.png
     :align: center
     :alt: View of the pos interface to register orders
 
@@ -87,14 +87,14 @@ table.
 
 To do so, select the table your customer is currently on.
 
-.. image:: media/restaurant_08.png
+.. image:: restaurant/restaurant_08.png
     :align: center
     :alt: View of the restaurant tables, one having a pending order
 
 Now, click on the transfer button and select the table to which you are transferring your
 customer.
 
-.. image:: media/restaurant_09.png
+.. image:: restaurant/restaurant_09.png
     :align: center
     :alt: View of the pos interface and transfer button. How to transfer customers from one table 
           to another
@@ -108,7 +108,7 @@ another one.
 Then, you can shift between your orders and process the payment
 when needed.
 
-.. image:: media/restaurant_10.png
+.. image:: restaurant/restaurant_10.png
     :align: center
     :alt: View of the - button, allowing employees to close/remove an order