[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/apps.xml

@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Copyright 2018 Tecnativa - Jairo Llopis
+     License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl). -->
+
+<template>
+    <t t-extend="AppsMenu">
+        <!-- App icons should be more than a text -->
+        <t t-jquery=".o_app &gt; t" t-operation="replace">
+            <t t-call="web_responsive.AppIcon"/>
+        </t>
+
+        <!-- Same hotkey as in EE -->
+        <t t-jquery=".full" t-operation="attributes">
+            <attribute name="accesskey">a</attribute>
+        </t>
+
+        <!-- Search bar -->
+        <t t-jquery="[t-as=app]" t-operation="before">
+            <div class="search-container form-row align-items-center mb-4 col-12">
+                <div class="search-input col-md-10 ml-auto mr-auto mb-2">
+                    <div class="input-group">
+                        <div class="input-group-prepend">
+                            <div class="input-group-text">
+                                <i class="fa fa-search"/>
+                            </div>
+                        </div>
+                        <input type="search"
+                               placeholder="Search menus..."
+                               class="form-control"/>
+                    </div>
+                </div>
+                <div class="search-results col-md-10 ml-auto mr-auto"/>
+            </div>
+        </t>
+    </t>
+
+    <!-- Separate app icon template, for easier inheritance -->
+    <t t-name="web_responsive.AppIcon">
+        <img class="o-app-icon"
+             t-attf-src="data:image/png;base64,#{app.web_icon_data}"/>
+        <span class="o-app-name">
+            <t t-esc="app.name"/>
+        </span>
+    </t>
+
+    <!-- A search result -->
+    <t t-name="web_responsive.MenuSearchResults">
+        <t t-foreach="results" t-as="result">
+            <t t-set="menu" t-value="widget._menuInfo(result.original)"/>
+            <div t-attf-class="o-menu-search-result dropdown-item col-12 ml-auto mr-auto #{result_first ? 'active' : ''}"
+                 t-attf-style="background-image:url('data:image/png;base64,#{menu.web_icon_data}')"
+                 t-att-data-menu-id="menu.id"
+                 t-att-data-action-id="menu.action_id"
+                 t-att-data-parent-id="menu.parent_id[0]"
+                 t-raw="result.string"/>
+        </t>
+    </t>
+</template>