Add translations to dependency proxy UI

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/app/views/groups/dependency_proxies/_url.html.haml

-%h5.prepend-top-20 Dependency proxy URL
+%h5.prepend-top-20= _('Dependency proxy URL')
 
 %div
   = text_field_tag :url, "#{group_url(@group)}/dependency_proxy/containers", class: 'js-dependency-proxy-url form-control', readonly: true
 
 .help-block.prepend-top-5
-  Contains #{@blobs_count} blobs of images (#{number_to_human_size(@blobs_total_size)})
+  = s_('Contains %{count} blobs of images (%{size})') % { count: @blobs_count, size: number_to_human_size(@blobs_total_size) }

ee/app/views/groups/dependency_proxies/show.html.haml

 - page_title "Dependency Proxy"
 
 .settings-header
-  %h4 Dependency proxy
+  %h4= _('Dependency proxy')
 
   %p
     - link_start = '<a href="%{url}">'.html_safe % { url: help_page_path('PLACEHOLDER') }

locale/gitlab.pot

@@ -3173,6 +3173,9 @@ msgstr ""
 msgid "ContainerRegistry|You can also use a %{deploy_token} for read-only access to the registry images."
 msgstr ""
 
+msgid "Contains %{count} blobs of images (%{size})"
+msgstr ""
+
 msgid "Contents of .gitlab-ci.yml"
 msgstr ""
 
@@ -3668,6 +3671,12 @@ msgstr ""
 msgid "Dependency Proxy"
 msgstr ""
 
+msgid "Dependency proxy"
+msgstr ""
+
+msgid "Dependency proxy URL"
+msgstr ""
+
 msgid "DependencyProxy|Toggle Dependency Proxy"
 msgstr ""