Change design of federation pages in admin UI (#17704)

* Change design of federation pages in admin UI

* Fix query performance in instance media attachments measure

* Fix reblogs being included in instance languages dimension

app/lib/admin/metrics/dimension/instance_accounts_dimension.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+class Admin::Metrics::Dimension::InstanceAccountsDimension < Admin::Metrics::Dimension::BaseDimension
+  include LanguagesHelper
+
+  def self.with_params?
+    true
+  end
+
+  def key
+    'instance_accounts'
+  end
+
+  protected
+
+  def perform_query
+    sql = <<-SQL.squish
+      SELECT accounts.username, count(follows.*) AS value
+      FROM accounts
+      LEFT JOIN follows ON follows.target_account_id = accounts.id
+      WHERE accounts.domain = $1
+      GROUP BY accounts.id, follows.target_account_id
+      ORDER BY value DESC
+      LIMIT $2
+    SQL
+
+    rows = ActiveRecord::Base.connection.select_all(sql, nil, [[nil, params[:domain]], [nil, @limit]])
+
+    rows.map { |row| { key: row['username'], human_key: row['username'], value: row['value'].to_s } }
+  end
+
+  def params
+    @params.permit(:domain)
+  end
+end