Allow users to update their email address (#1745)

* Change email address

* Email confirmation

* Email change test

* Lint

* Schema reset

* Set test email sender

* Select specific user fixture

* Refactor/cleanup

* Remove unused email_confirmation_token

* Current user would never be true

* Fix translation test failures

test/models/user_test.rb

@@ -38,8 +38,8 @@ class UserTest < ActiveSupport::TestCase
   end
 
   test "email address is normalized" do
-    @user.update!(email: " User@ExAMPle.CoM ")
-    assert_equal "user@example.com", @user.reload.email
+    @user.update!(email: " UNIQUE-User@ExAMPle.CoM ")
+    assert_equal "unique-user@example.com", @user.reload.email
   end
 
   test "display name" do