Move topics out of gitlab-basics directory to topics directory

app/helpers/projects_helper.rb

doc/editor_extensions/neovim/neovim_troubleshooting.md

doc/gitlab-basics/add-file.md

doc/gitlab-basics/feature_branch_workflow.md

doc/gitlab-basics/start-using-git.md

doc/topics/git/add_files.md

doc/topics/git/commands.md

doc/topics/git/get_started.md

doc/topics/git/index.md

doc/tutorials/learn_git.md

doc/user/project/merge_requests/index.md

doc/user/project/repository/code_suggestions/index.md

doc/user/project/repository/index.md

locale/gitlab.pot

spec/features/projects/show/no_password_spec.rb

spec/helpers/projects_helper_spec.rb