Revert #6479, hide sensitive text/images from OpenGraph previews (#6818)

Display summary of attachments in description, and mark up content
warning if present, e.g.:

    Attached: 3 images · Content warning: Dota 2

When text is not supposed to be hidden, it looks more like:

    Attached: 3 images

    Here is the text of the toot

With #6817, multilinguagility should be assured...

config/i18n-tasks.yml

@@ -62,3 +62,4 @@ ignore_unused:
   - 'errors.429'
   - 'admin.accounts.roles.*'
   - 'admin.action_logs.actions.*'
+  - 'statuses.attached.*'

config/locales/en.yml

@@ -634,6 +634,15 @@ en:
     two_factor_authentication: Two-factor Auth
     your_apps: Your applications
   statuses:
+    attached:
+      description: 'Attached: %{attached}'
+      image:
+        one: "%{count} image"
+        other: "%{count} images"
+      video:
+        one: "%{count} video"
+        other: "%{count} videos"
+    content_warning: 'Content warning: %{warning}'
     open_in_web: Open in web
     over_character_limit: character limit of %{max} exceeded
     pin_errors: