Add meta tags for OGP to following & follow page (#2052)

* Add meta tags for OGP to following & follow page

* simplify render helper

* Follow up #2133

* og:type is only accounts/show

* revert accounts/{following,followers}

app/views/following_accounts/index.html.haml

@@ -1,6 +1,9 @@
 - content_for :page_title do
   = t('accounts.people_followed_by', name: display_name(@account))
 
+- content_for :header_tags do
+  = render 'accounts/og', account: @account
+
 = render 'accounts/header', account: @account
 
 = render 'accounts/follow_grid', accounts: @accounts