Account deletion (#3728)

* Add form for account deletion

* If avatar or header are gone from source, remove them

* Add option to have SuspendAccountService remove user record, add tests

* Exclude suspended accounts from search

app/services/suspend_account_service.rb

@@ -1,9 +1,10 @@
 # frozen_string_literal: true
 
 class SuspendAccountService < BaseService
-  def call(account)
+  def call(account, remove_user = false)
     @account = account
 
+    purge_user if remove_user
     purge_content
     purge_profile
     unsubscribe_push_subscribers
@@ -11,6 +12,10 @@ class SuspendAccountService < BaseService
 
   private
 
+  def purge_user
+    @account.user.destroy
+  end
+
   def purge_content
     @account.statuses.reorder(nil).find_each do |status|
       # This federates out deletes to previous followers