[FIX] base, web: settings page, use breadcrumb for title

Use .breadcrumb class to ensure that the page title design will match
all the other pages.

addons/web/static/src/legacy/scss/base_settings.scss

@@ -26,7 +26,7 @@
             flex-flow: row wrap;
             width: 100%;
 
-            .title, .o_setting_search {
+            .o_settings_title, .o_setting_search {
                 flex: 1 0 auto;
                 width: map-get($o-extra-grid-breakpoints, vsm) / 2;
             }

odoo/addons/base/views/res_config_settings_views.xml

@@ -8,7 +8,9 @@
                 <form string="Settings" class="oe_form_configuration o_base_settings" js_class="base_settings">
                     <div class="o_control_panel">
                         <div class="o_panel">
-                            <div class="title h2 mb0 mt4 text-muted d-none d-md-block">Settings</div>
+                            <ol role="navigation" class="breadcrumb o_settings_title d-none d-md-block">
+                                <li class="breadcrumb-item active">Settings</li>
+                            </ol>
                             <div class="o_setting_search">
                                 <input type="text" class="searchInput" placeholder="Search..."/>
                                 <span class="searchIcon"><i class="fa fa-search" role="img" aria-label="Search" title="Search"/></span>