[REF][MOV] documentation apocalypse

Prior to this commit, the Odoo documentation was mainly split between
two repositories: odoo/odoo/doc and odoo/documentation-user. Some bits
of documentation were also hosted elsewhere (e.g., wiki, upgrade, ...).
This was causing several problems among which:
  - The theme, config, Makefile, and similar technical resources had to
    be duplicated. This resulted in inconsistent layout, features, and
    build environments from one documentation to another.
  - Some pages did not fit either documentation as they were relevant
    for both users and developers. Some were relevant to neither of the
    two (e.g., DB management).
  - Cross-doc references had to be absolute links and they broke often.
  - Merging large image files in the developer documentation would bloat
    the odoo/odoo repository. Some contributions had to be lightened to
    avoid merging too many images (e.g., Odoo development tutorials).
  - Long-time contributors to the user documentation were chilly about
    going through the merging process of the developer documentation
    because of the runbot, mergebot, `odoo-dev` repository, etc.
  - Some contributors would look for the developer documentation in the
    `odoo/documentation-user` repository.
  - Community issues about the user documentation were submitted on the
    `odoo/odoo` repository and vice-versa.

Merging all documentations in one repository will allow us to have one
place, one theme, one work process, and one set of tools (build
environment, ...) for all of the Odoo docs.

As this is a good opportunity to revamp the layout of the documentation,
a brand new theme replaces the old one. It features a new way to
navigate the documentation, centered on the idea of always letting the
reader know what is the context (enclosing section, child pages, page
structure ...) of the page they are reading. The previous theme would
quickly confuse readers as they navigated the documentation and followed
cross-application links.

The chance is also taken to get rid of all the technical dangling parts,
performance issues, and left-overs. Except for some page-specific JS
scripts, the Odoo theme Sphinx extension is re-written from scratch
based on the latest Sphinx release to benefit from the improvements and
ease future contributions.

task-2351938
task-2352371
task-2205684
task-2352544

Closes #945

content/applications/sales/point_of_sale/payment/vantiv.rst

@@ -0,0 +1,46 @@
+=============================================
+Connect a Vantiv Payment Terminal to your PoS
+=============================================
+
+Connecting a Vantiv payment terminal allows you to offer a fluid payment
+flow to your customers and ease the work of your cashiers.
+
+.. note::
+		Please note MercuryPay only operates with US and Canadian banks, making
+		this procedure only suitable for North American businesses.
+
+Configuration
+=============
+
+Configure the Payment Method
+----------------------------
+
+First, go in the general settings of the POS app, and activate the
+Vantiv setting.
+
+.. image:: media/vantiv_01.png
+    :align: center
+
+Back in *Point of Sale > Configuration > Point of Sale*, go in the
+payments section and access your payment methods. Create a new payment
+method for Vantiv, select the payment terminal option Vantiv, and create
+new Vantiv credentials.
+
+.. image:: media/vantiv_02.png
+    :align: center
+
+To create new Vantiv credentials, fill in your merchant ID and password,
+then save. Make sure the credentials you just created are selected, then
+save the payment method.
+
+.. image:: media/vantiv_03.png
+    :align: center
+
+Pay with a Payment Terminal
+===========================
+
+In your PoS interface, at the moment of the payment, select your Vantiv
+payment method and… that’s all.
+
+.. image:: media/vantiv_04.png
+    :align: center