[MIG] web_responsive: Migrate to v12 and refactor

This migration includes a full refactoring to make this module more
maintainable. Some things that have changed:

- Removed external libraries.
- Change Less for Scss.
- Reduce ES and XML to the minimal required needs.
- Implement as much features as possible with just Scss.
- Remove copyright from `__init__.py` files.
- Trigger the new hotkeys system from Odoo v12 with `Shift+Alt` instead
  of just `Alt`, and restore some good old hotkeys (`E` for "Edit",
  `D` for "Discard", and `A` for "Apps menu").
  See https://github.com/odoo/odoo/issues/30068 on the matter.
- Control panel breadcrumbs are collapsed into a single backwards icon.
- Add FA icons to most common buttons in control panel.
- Hide text in XS for those buttons, to have a slicker phone experience.
- Lots of gifs in the README!

web_responsive/static/src/xml/navbar.xml

@@ -1,11 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- Copyright 2017 Jairo Llopis <jairo.llopis@tecnativa.com>
+<!-- Copyright 2017-2018 Tecnativa - Jairo Llopis
      License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl). -->
 
 <template>
-    <t t-extend="SwitchCompanyMenu">
-        <t t-jquery=".oe_topbar_name" t-operation="before">
-            <i class="fa fa-building visible-xs-inline-block"/>
+    <t t-extend="Menu">
+        <t t-jquery=".o_menu_apps" t-operation="after">
+            <!-- Hamburger button to show submenus in sm screens -->
+            <button class="o-menu-toggle d-md-none"
+                    data-toggle="collapse"
+                    data-target=".o_main_navbar .o_menu_sections">
+                <i class="fa fa-bars"/>
+            </button>
         </t>
     </t>
 </template>