Add federation support for the "hide network" preference (#11673)

* Change ActivityPub follower/following collections to not link first page

* Add support for hiding followers and following of remote users

* Switch to using a single `hide_collections` column

* Address code style remarks

db/migrate/20191212163405_add_hide_collections_to_accounts.rb

@@ -0,0 +1,5 @@
+class AddHideCollectionsToAccounts < ActiveRecord::Migration[5.2]
+  def change
+    add_column :accounts, :hide_collections, :boolean
+  end
+end