Add missed files

Use correct method

Implement review feedback

Add missing frozen_string_literal

Squash 5 commits

Update the login page object and related code so that a user can be
registered when LDAP is enabled

[QA] Improve the fork scenario to take a username and password instead of always creating a new user

Fixes https://gitlab.com/gitlab-org/quality/staging/issues/2.
Signed-off-by: Rémy Coutable <remy@rymai.me>