HL e2e tests

There were so many issues with installing GDK. I have followed some of the issues.

• gitlab-org/gitlab-development-kit#619 (closed)
• gitlab-org/gitlab-development-kit#392 (closed)
• gitlab-org/gitlab-development-kit#424 (closed)
• gitlab-org/gitlab-development-kit#578 (closed)

Also, I tried to follow the pattern (https://about.gitlab.com/handbook/values/#minimum-viable-change-mvc)

There are few files get rubocop "Layout/TrailingWhitespace: Trailing whitespace detected." warning.

Steps:

1. As a "root" user, create a new "developer-user" user.
   => 1_manage/project/add_project_member_spec.rb

2. As a "root" user, create a project. => manage/project/add_project_member_spec.rb

3. Add the "developer-user" user to the project. => manage/project/add_project_member_spec.rb

4. As the "developer-user" user, commit a file to the project using SSH in a new branch. => 3_create/merge_request/assign_merge_request_spec.rb

5. As the "developer-user" user, create a merge request (MR) and assign it to the "root" user for review. => 3_create/merge_request/assign_merge_request_spec.rb

6. As the "root" user, suggest a change using the "Insert suggestion" button. => 3_create/merge_request/apply_merge_request_suggestion_spec.rb

7. As the "developer-user" user, apply the change. => 3_create/merge_request/apply_merge_request_suggestion_spec.rb

8. As the "root" user, merge the MR. => 3_create/merge_request/apply_merge_request_suggestion_spec.rb

9. As the "root" user, ensure that the repository now has the file with the suggested changes. => 3_create/merge_request/apply_merge_request_suggestion_spec.rb

Regarding SSH commit, and docker images running, I couldn't have run successfully.

Thanks!