[FIX] point_of_sale: remove references to self-checkout in docs

Version 7 (and saas-3) had a self-checkout mode that was removed in
8. There are still some fields that reference the feature in
point_of_sale.py but they're obsolete and unused in the
frontend.

Both README.md and static/description/index.html (and thus
odoo.com/apps) still referenced these features.

opw-666328

addons/point_of_sale/README.md

@@ -87,15 +87,6 @@ your store's efficiency.
 No more hassle of having to integrate softwares: get all your sales and
 inventory operations automatically posted in your G/L.
 
-Self-checkout Interface
------------------------
-
-Reduce costs by limitting the number of required cashiers. The self-checkout
-mode allows customers to scan products and pay by themselves with a dedicated
-and super easy user interface.
-
-Use lights and sounds to control the checkout distantly.
-
 Unified Data Amongst All Shops
 ------------------------------
 

addons/point_of_sale/static/description/index.html

@@ -182,26 +182,6 @@
     </div>
 </section>
 
-<section class='oe_container oe_dark'>
-    <div class='oe_row'>
-        <h2 class='oe_slogan'>Self-checkout Interface</h2>
-        <div class='oe_span6'>
-            <p>
-            Reduce costs by limitting the number of required cashiers.
-			The self-checkout mode allows customers to scan products and pay by
-			themselves with a dedicated and super easy user interface.
-            </p>
-            <p>
-            Use lights and sounds to control the checkout distantly.
-            </p>
-        </div>
-        <div class='oe_span6'>
-            <img class="oe_picture oe_screenshot" src="pos_checkout.jpg">
-        </div>
-    </div>
-</section>
-
-
 <section class='oe_container'>
     <div class='oe_row'>
         <h2 class='oe_slogan'>Unified Data Amongst All Shops</h2>