Add remote translation button

- Create partial to render remote translation button. This button will
  send remote_translations as json to remote translations controller.
- Add locales
- Add styles

Co-Authored-By: alessandro <agileontheweb@gmail.com>

app/assets/stylesheets/layout.scss

@@ -474,6 +474,26 @@ header {
     }
   }
 
+  .remote-translations-button {
+
+    .callout {
+      margin: 0;
+      padding: rem-calc(6);
+
+      [type="submit"] {
+        background: none;
+        border: 0;
+        cursor: pointer;
+        font-weight: bold;
+        color: $brand;
+
+        &:hover {
+          text-decoration: underline;
+        }
+      }
+    }
+  }
+
   .external-links {
     float: none;
     padding: rem-calc(6) 0;

app/views/shared/_remote_translations_button.html.erb

@@ -0,0 +1,11 @@
+<div class="remote-translations-button callout primary text-center">
+  <% if display_remote_translation_button?(remote_translations) %>
+    <%= form_tag remote_translations_path do %>
+      <%= hidden_field_tag :remote_translations, remote_translations.to_json %>
+      <%= t("remote_translations.text") %>
+      <%= submit_tag t("remote_translations.button") %>
+    <% end %>
+  <% else %>
+    <%= t("remote_translations.all_remote_translations_enqueued_text") %>
+  <% end %>
+</div>

config/locales/en/general.yml

@@ -1034,5 +1034,7 @@ en:
     borda: Borda votation
     dowdall: Dowdall votation
   remote_translations:
+    text: The content of this page is not available in your language
     create:
       enqueue_remote_translation: Translations have been correctly requested.
+    button: Translate page

config/locales/es/general.yml

@@ -1031,5 +1031,7 @@ es:
     borda: Votación con recuento Borda
     dowdall: Votación con recuento Dowdall
   remote_translations:
+    text: El contenido de esta página no está disponible en tu idioma
     create:
       enqueue_remote_translation: Se han solicitado correctamente las traducciones.
+    button: Traducir página