GitLab.com integration: refactoring

app/controllers/import/github_controller.rb

app/controllers/import/gitlab_controller.rb

app/views/import/github/create.js.haml

app/views/import/github/status.html.haml

app/views/import/gitlab/create.js.haml

app/views/import/gitlab/status.html.haml

app/views/projects/new.html.haml

config/routes.rb

doc/integration/gitlab.md

lib/gitlab/github_import/client.rb

lib/gitlab/github_import/importer.rb

lib/gitlab/gitlab_import/client.rb

lib/gitlab/gitlab_import/importer.rb

lib/gitlab/import_formatter.rb

spec/controllers/import/github_controller_spec.rb

spec/controllers/import/gitlab_controller_spec.rb