[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#2026

content/applications/finance/accounting/bank/reconciliation/reconciliation_models.rst

@@ -35,7 +35,7 @@ When you are reconciling an entry with an *Open Balance*, you can use the button
 the *Manual Operations* tab to pre-fill all the values automatically, before validating the
 reconciliation. Each button is a different Reconciliation Model.
 
-.. image:: media/reconciliation_models_button.png
+.. image:: reconciliation_models/reconciliation_models_button.png
    :align: center
    :alt: Example of a Reconciliation Model with a write-off button in Odoo Accounting
 
@@ -47,7 +47,7 @@ Suggest counterpart values
 This type of Reconciliation Model suggests immediately counterpart values that only need to be
 validated. This automation is based on a set of rules defined in the reconciliation model.
 
-.. image:: media/reconciliation_models_suggestion.png
+.. image:: reconciliation_models/reconciliation_models_suggestion.png
    :align: center
    :alt: Example of a Reconciliation Model that suggests counterpart values in Odoo Accounting
 
@@ -60,7 +60,7 @@ This type of Reconciliation Model automatically selects the right Customer Invoi
 that matches the payment. All that is left to do is to validate the entry. This automation is based
 on a set of rules defined in the reconciliation model.
 
-.. image:: media/reconciliation_models_match.png
+.. image:: reconciliation_models/reconciliation_models_match.png
    :align: center
    :alt: Example of a Reconciliation Model that matches existing invoices and bills automatically
          in Odoo Accounting
@@ -73,7 +73,7 @@ Reconciliation --> Reconciliation Models`. Alternatively, you can also open this
 Accounting Overview, by going to your Bank Journal card, clicking on the three little dots, and then
 on *Reconciliation Models*.
 
-.. image:: media/reconciliation_models_overview.png
+.. image:: reconciliation_models/reconciliation_models_overview.png
    :align: center
    :alt: Open the Reconciliation Model menu from the overview dashboard in Odoo Accounting
 
@@ -106,7 +106,7 @@ Define here all the conditions that are required for a Reconciliation Model to b
    will be applied. The sequence is simply the order of the models in the *list view*. They can be
    rearranged by dragging-and-dropping the handle next to the name.
 
-.. image:: media/reconciliation_models_conditions.png
+.. image:: reconciliation_models/reconciliation_models_conditions.png
    :align: center
    :alt: Conditions for the Reconciliation Model to be applied in Odoo Accounting
 
@@ -118,7 +118,7 @@ This section comprises the values that are applied by the Reconciliation Model.
 If the value to reconcile needs to be written-off in two separate accounts, click on *Add a second
 line*.
 
-.. image:: media/reconciliation_models_counterparts.png
+.. image:: reconciliation_models/reconciliation_models_counterparts.png
    :align: center
    :alt: Counterparts values of a Reconciliation Model in Odoo Accounting